Static seals, compositions, and methods of making the same

ABSTRACT

A static sealing member is provided that includes a composition having a silane-crosslinked polyolefin elastomer with a density less than 0.90 g/cm 3 . The static sealing member can exhibit a compression set of from about 5.0% to about 35.0%, as measured according to ASTM D 395 ( 22  hrs @ 70° C.). The silane-crosslinked polyolefin elastomer can include a first polyolefin having a density less than 0.86 g/cm 3 , a second polyolefin having a crystallinity less than 40%, a silane crosslinker, a grafting initiator, and a condensation catalyst.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent Application No. 62/497,954 filed Dec. 10, 2016,entitled “WEATHERSTRIP, COMPOSITION INCLUDING SILANE-GRAFTED POLYOLEFIN,AND PROCESS OF MAKING A WEATHERSTRIP,” which is herein incorporated byreference in its entirety.

FIELD OF THE DISCLOSURE

The disclosure generally relates to compositions that may be used toform static seals, and more particularly, to compositions used to formstatic seals in vehicles and methods for manufacturing thesecompositions and seals.

BACKGROUND OF THE DISCLOSURE

The motor vehicle industry is continuously manufacturing and developingsealing elements and sections having low friction and abrasionresistance properties. These elements and sections can be extruded fromcertain polymeric materials. One example of an extrudedabrasion-resistant section is a static seal. Static seals, such asweatherstrips, are mounted on an automobile window to provide a sealbetween the glass and the automobile body to prevent wind noise, waterleaks, and particulate matter from entering the automobile.

Weatherstrip formulations that make contact with various sections ofautomotive glass doors, and/or other sections of an automotive bodytraditionally utilize either thermoplastic vulcanizates (TPV) orethylene propylene diene monomer (EPDM) rubber to achieve desiredsealing performance. TPVs are relatively easy to process, but sealingperformance can be limited in terms of resilience or sealing abilityover time and material costs tend to be high. Similarly, EPDM rubberformulations often require many ingredients (e.g., carbon black,petroleum-based oil, zinc oxide, miscellaneous fillers such as calciumcarbonate or talc, processing aids, curatives, blowing agents, and manyother materials to meet performance requirements), which tend toincrease their material cost.

EPDM-based seals are also costly from a process stand point. The EPDMconstituent ingredients are typically mixed together in a one-ortwo-step process prior to shipping to an extrusion facility. At theextrusion facility, the ingredients and rubber compound(s) are extrudedtogether to form a final material, which is subsequently formed intoautomotive glass contacting weatherstrips. Hence, the extrusion processused to manufacture weatherstrips can include many stages, depending onthe type of EPDM or other types of resins, and may additionally requirelong lengths of curing ovens. For example, extrusion lines of up to 80yards in length that are powered by natural gas and/or electricity maybe required. Much of the natural gas and/or electricity is used to fuelhot air ovens, microwaves, infrared ovens, or other types of equipmentused to vulcanize the EPDM rubber compounds. The vulcanization processalso produces fumes that must be vented and monitored to comply withenvironmental requirements. Overall, the processes used to fabricatethese traditional EPDM-based seals can be very time consuming, costly,and environmentally unfriendly.

Mindful of the drawbacks associated with current TPV and EPDM-basedsealing technologies, the automotive industry has a need for thedevelopment of new compositions and methods for manufacturingweatherstrips and seals that are simpler, lighter in weight, lower incost, have superior long-term load loss (LLS) (i.e., ability to seal theglass and window for a long term), and are more environmentallyfriendly.

SUMMARY OF THE DISCLOSURE

According to one aspect of the present disclosure, a static sealingmember is disclosed.

The static sealing member includes a composition comprising asilane-crosslinked polyolefin elastomer having a density less than 0.90g/cm³. The static sealing member exhibits a compression set of fromabout 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @70° C.).

According to another aspect of the present disclosure, asilane-crosslinked polyolefin blend is disclosed. The silane-crosslinkedpolyolefin blend includes a first polyolefin having a density less than0.86 g/cm³, a second polyolefin having a crystallinity less than 40%,and a silane crosslinker. The silane-crosslinked polyolefin blendexhibits a compression set of from about 5.0% to about 35.0%, asmeasured according to ASTM D 395 (22 hrs @ 70° C.).

According to a further aspect of the present disclosure, a method formaking a static sealing member is disclosed. The method includes thesteps of: extruding a first polyolefin having a density less than 0.86g/cm³, a second polyolefin having a crystallinity less than 40%, asilane crosslinker and a grafting initiator together to form asilane-grafted polyolefin blend; extruding the silane-grafted polyolefinblend and a condensation catalyst together to form asilane-crosslinkable polyolefin blend; molding the silane-crosslinkablepolyolefin blend into an uncured static sealing element; andcrosslinking the crosslinkable-polyolefin blend at an ambienttemperature and an ambient humidity to form the element into the staticsealing member having a density from about 0.85 g/cm³ to about 0.89g/cm³. The static sealing member exhibits a compression set of fromabout 5.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @70° C.).

These and other aspects, objects, and features of the present disclosurewill be understood and appreciated by those skilled in the art uponstudying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a front perspective view of a vehicle having a plurality ofweatherstrip static seals according to some aspects of the presentdisclosure;

FIG. 2 is a side perspective view of a front door portion of the vehiclepresented in FIG.1;

FIG. 3 is a cross-sectional view of a beltline weatherstrip sealaccording to some aspects of the present disclosure;

FIG. 4 is a cross-sectional view of a below-belt weatherstrip sealaccording to some aspects of the present disclosure;

FIG. 5 is a schematic view of a plurality of static seals used in thevehicle presented in FIG. 1 according to some aspects of the presentdisclosure;

FIGS. 6A-6H are a variety of cross-sectional views of the representativestatic seals provided in FIG. 5 according to some aspects of the presentdisclosure;

FIG. 7 is a schematic reaction pathway used to produce asilane-crosslinked polyolefin elastomer according to some aspects of thepresent disclosure;

FIG. 8 is a flow diagram of a method for making a static seal with asilane-crosslinked polyolefin elastomer using a two-step Sioplasapproach according to some aspects of the present disclosure;

FIG. 9A is a schematic cross-sectional view a reactive twin-screwextruder according to some aspects of the present disclosure;

FIG. 9B is a schematic cross-sectional view a single-screw extruderaccording to some aspects of the present disclosure;

FIG. 10 is a flow diagram of a method for making a static seal with asilane-crosslinked polyolefin elastomer using a one-step Monosilapproach according to some aspects of the present disclosure;

FIG. 11 is a schematic cross-sectional view a reactive single-screwextruder according to some aspects of the present disclosure;

FIG. 12 is a graph illustrating the stress/strain behavior of a densesilane-crosslinked polyolefin elastomer compared to EPDM compounds;

FIG. 13 is a graph illustrating the lip compression set of inventivedense silane-crosslinked polyolefin elastomers and comparativepolyolefin elastomers;

FIG. 14 is a graph illustrating the lip set recovery of inventive densesilane-crosslinked polyolefin elastomers and comparative polyolefinelastomers;

FIG. 15 is a graph illustrating the relaxation rate of several densesilane-crosslinked polyolefin elastomers and comparative polyolefinelastomers;

FIG. 16 is a graph illustrating the stress/strain behavior of aninventive dense silane-crosslinked polyolefin elastomer;

FIG. 17 is a graph illustrating the compression set of EPDM, TPV, and adense silane-crosslinked polyolefin elastomer as plotted with respect tovarious test temperatures and time conditions;

FIG. 18 is a graph illustrating the compression set of EPDM, TPV, and adense silane-crosslinked polyolefin elastomer as plotted with respect totemperatures ranging from 23° C. to 175° C.; and

FIG. 19 is a graph illustrating the compression set of TPV and severaldense silane-crosslinked polyolefin elastomers as plotted with respectto 23° C. and 125° C. temperatures.

DETAILED DESCRIPTION OF THE EMBODIMENTS

For purposes of description herein the terms “upper,” “lower,” “right,”“left,” “rear,” “front,” “vertical,” “horizontal,” and derivativesthereof shall relate to the static seals of the disclosure as orientedin the vehicle shown in FIG. 1. However, it is to be understood that thedevice may assume various alternative orientations and step sequences,except where expressly specified to the contrary. It is also to beunderstood that the specific devices and processes illustrated in theattached drawings, and described in the following specification aresimply exemplary embodiments of the inventive concepts defined in theappended claims. Hence, specific dimensions and other physicalcharacteristics relating to the embodiments disclosed herein are not tobe considered as limiting, unless the claims expressly state otherwise.

All ranges disclosed herein are inclusive of the recited endpoint andindependently combinable (for example, the range of “from 2 to 10” isinclusive of the endpoints, 2 and 10, and all the intermediate values).The endpoints of the ranges and any values disclosed herein are notlimited to the precise range or value; they are sufficiently impreciseto include values approximating these ranges and/orvalues.

A value modified by a term or terms, such as “about” and“substantially,” may not be limited to the precise value specified. Theapproximating language may correspond to the precision of an instrumentfor measuring the value. The modifier “about” should also be consideredas disclosing the range defined by the absolute values of the twoendpoints. For example, the expression “from about 2 to about 4” alsodiscloses the range “from 2 to 4.”

As used herein, the term “and/or,” when used in a list of two or moreitems, means that any one of the listed items can be employed by itself,or any combination of two or more of the listed items can be employed.For example, if a composition is described as containing components A,B, and/or C, the composition can contain A alone; B alone; C alone; Aand B in combination; A and C in combination; B and C in combination; orA, B, and C in combination.

Referring to FIGS. 1-6H, various static sealing members are provided. Ingeneral, the static sealing members of the disclosure include acomposition having a silane-crosslinked polyolefin elastomer with adensity less than 0.90 g/cm³. The static sealing member can exhibit acompression set of from about 5.0% to about 35.0% measured according toASTM D 395 (22 hrs @ 70° C.). The silane-crosslinked polyolefinelastomer can be produced from a blend including a first polyolefinhaving a density less than 0.86 g/cm³, a second polyolefin having acrystallinity less than 40° C., a silane crosslinker, a graftinginitiator, and a condensation catalyst.

Referring to FIG. 1, vehicle 10 is provided having a variety of staticsealing members 12 (e.g., weatherstrip seals). The vehicle 10 is shownas a sports utility vehicle (SUV) but the type of vehicle 10 is notmeant to be limiting and can include, for example, a car, minivan,truck, commercial vehicle, or any other wheeled motorized vehicle. Thevehicle 10 and the static sealing members 12 described herein are forillustrative purposes only and are not to be construed as limiting toonly vehicles 10, for example, the static sealing members 12 couldadditionally be used in the building construction industry, thetransportation industry, the electronics industry, the footwearindustry, and the roofing industry.

Referring now to FIG. 2, a portion of the vehicle 10 (see FIG. 1)including a front door 14 is provided. The door 14 includes a windowopening 18 and a window 22 that can be selectively raised and loweredrelative to the window opening 18. The static sealing member 12 in theform of a window weatherstrip seal 26 surrounds perimeter portions ofthe window 22 (e.g., side and upper portions when the window is closed).The window weatherstrip seal 26 may be used to seal portions of the door14 against the surface and/or edges of the glass window 22. The windowweatherstrip seal 26 may be formed using separate weatherstrip portionsincluding a beltline weatherstrip seal 12, 34 (see also FIG. 3), and abelow-belt weatherstrip seal 12, 74 (see also FIG. 4) positioned infirst and second belt portions 38, 42 that engage different perimeterportions of the window 22. The first and second belt portions 38, 42 canbe located in an interior cavity of the door 14 and the below-beltweatherstrip seal 74 can be positioned within the first and second beltportions 38, 42. In some aspects, the beltline and below-beltweatherstrip seals 34, 74 can be integrally joined together as a moduleor the combined window weatherstrip seal 26. An inner edge of the windowopening 18, as defined by the door 14, may be referred to as a beltline30. Extending along the beltline 30 is the beltline weatherstrip seal 34that joins the window 22 to the surrounding door 14 and makes up aportion of the window weatherstrip seal 26.

The term “weatherstrip”, as used herein, is synonymous with the word“seal.” The term “seal”, as used herein, means a device or substancethat is used to join two surfaces together. The surfaces used herein mayinclude the various types of surfaces found on, for example,automobiles, structures, windows, roofs, electronic devices, footwear,and/or any other industry or product where seals can be used to helpminimize and/or eliminate the transmission of noise, water, orparticulate matter through the respective surfaces.

The seals used for the various static sealing members 12 (e.g.,weatherstrip seals 26) disclosed herein may be fabricated ormanufactured from one or more different silane-crosslinked polyolefinelastomers. In aspects where the static seal includes more than one typeof silane-crosslinked polyolefin elastomer, the differentsilane-crosslinked polyolefin elastomers can each make up one or moredifferent strips, gripping portions, bodies, pins, and/or surfaces ofthe static seal. As noted earlier, static seals generally have little orno relative motion between the mating surfaces being sealed. In someaspects, the static seals are made entirely of a densesilane-crosslinked polyolefin elastomer. As used herein, a “dense”silane-crosslinked polyolefin elastomer has a density of less than 0.90g/cm³. The synthesis and processing methods used to produce this densesilane-crosslinked polyolefin elastomer and its specialized materialproperties are disclosed herein.

In other aspects, the static seals may additionally include one or moreportions made from a micro-dense silane-crosslinked polyolefinelastomer, as typically used in micro-dense seals. Micro-dense seals aregenerally used where there is little to moderate motion between themating surfaces being sealed. As used herein, a “micro-dense”silane-crosslinked polyolefin elastomer includes a microencapsulatedfoaming agent and has a density less than 0.70 g/cm³ or, morespecifically, a density from about 0.60 g/cm³ to about 0.69 g/cm³.

In still other aspects, the static seals may additionally include one ormore portions made from a sponge silane-crosslinked polyolefinelastomer, as typically used in dynamic seals. Dynamic seals aregenerally used when there is motion between the mating surfaces beingsealed where a compressive foam could be applied to seal the surfaces.As used herein, a “dynamic” or “sponge” silane-crosslinked polyolefinelastomer includes a chemical and/or physical foaming agent and has adensity less than 0.60 g/cm³ or, more specifically, a density from about0.50 g/cm³to about 0.59 g/cm³.

Referring now to FIG. 3, a cross-sectional view of the windowweatherstrip seal 26 in the form of the beltline weatherstrip seal 34(see also FIG. 2) is provided. The beltline weatherstrip seal 34 caninclude a body 46 formed as an inverted, generally U-shaped componenthaving first and second legs 50, 54 with inwardly extending grippingportions 58 that engage a door panel 62. In some aspects, the beltlineweatherstrip seal 34 can be made from a dense silane-grafted polyolefinelastomer. The beltline weatherstrip seal 34 can further include a seallip 66 that is flexible relative to the body 46, and may be formed of adifferent material (e.g., a lower durometer rubber or plastic) than thebody 46. A low friction material 70 (e.g., graphite powder) can bepositioned along that portion of the seal lip 66 that is configured forsliding engagement with the window 22. In some aspects, the beltlineweatherstrip seal 34 can be formed as a co-extruded structure where thedifferent regions or portions of the integrated beltline weatherstripseal 34 are formed from different materials in order to serve differentfunctions. For example, the body 46 may be a higher durometer materialwhile the seal lip 66 requires flexibility and thus is preferably alower durometer material for better sealing as well as to have a lowfriction coating which can be co-extruded, spray coated or flocked.

Referring now to FIG. 4, a cross-sectional view of the windowweatherstrip seal 26 in the form of the below-belt weatherstrip seal 74(see also FIG. 2) is provided. In some aspects, the below-beltweatherstrip seal 74 may have an outer rigid support member 78 providedas a generally U-shaped component that receives or supports thebelow-belt weatherstrip seal 74. The member 78 can include upstandingfirst and second legs 82, 86 that form a channel base 90 which canreceive the below-belt weatherstrip seal 74. The below-belt weatherstripseal 74 may be unsupported, i.e., in this configuration the below-beltweatherstrip seal 74 does not have a rigid support member encased withinthe rubber or EPDM extrusion of which it is made. First and second legs94, 98 of the below-belt weatherstrip seal 74 extend generally upwardlyand outwardly from a base portion 102, giving the below-beltweatherstrip seal 74 a generally U-shaped conformation adapted toreceive a perimeter edge of the window 22. First and second retainingflanges 106, 110 are provided along outer edges of the base portion 102while first and second flexible seal lips 114, 118 are flexibly joinedat outer ends of the respective first and second legs 94, 98. The firstand second flexible seal lips 114, 118 and the first and secondretaining flanges 106, 110 may be formed of different hardnesspolyolefin compounds than the remaining rubber of the below-beltweatherstrip seal 74. Further, those portions of the below-beltweatherstrip seal 74 including the first and second legs 94, 98 and baseportion 102 can be adapted to engage the window 22 using a hardenedsurface (e.g., metal oxides and carbon allotropes), while the first andsecond seal lips 114, 118 may have a low friction surface (e.g.,graphite powder and polytetrafluoroethylene) to engage the window 22surface.

Referring to FIG. 5 and FIGS. 6A-6H, an isolated exploded schematic viewof a plurality of static sealing members 12 in the form of variousweatherstrip seals that can be used in the vehicle 10 (see FIG. 1) isprovided. The static weatherstrip seals provided in FIG. 5 areconfigured to be mounted along windows or other glass portions of thevehicle 10 and the respective doors and body portions they come intocontact with in order to help minimize and/or eliminate the transmissionof noise, water, or particulate matter. The static sealing member 12configured to be coupled between the door 14 (see FIG. 2) and window 22may include an outer belt static seal 122 and an inner belt static seal126 (see also FIGS. 6A and 6B, respectively). A pillar bracket staticseal 130 may be used to seal a portion of the door 14 to the window 22of the vehicle 10 (see also FIGS. 1 and 6C). An inner belt static seal134 (see also FIG. 6D) can extend along the beltline 30 (see FIG. 2) tojoin the window 22 to the surrounding door 14 (see FIG. 2). The innerbelt static seal 134 is provided as an alternate embodiment of thebeltline weatherstrip seal 34 provided in FIG. 3A. A front pillar staticseal 138 (see FIG. 6E), a rear pillar static seal 142 (see FIG. 6F), afirst center pillar static seal 146 (see FIG. 6G), and a second centerpillar seal 150 (see FIG. 6H) may each be positioned along therespective support pillars (not shown) of the door 14 to help stabilizethe static sealing members 12 and prevent the transmission of noise,water, or particulate matter.

Referring now to FIGS. 6A-6H, a variety of cross-sectional views of thestatic sealing members 12 depicted in FIG. 5 are provided that include:the outer belt static seal 122, the inner belt static seal 126, thepillar bracket static seal 130, the inner belt static seal 134, thefront pillar static seal 138, the rear pillar static seal 142, and thecenter pillar static seal 146. The structures of each of the staticsealing members 12 may be varied based on the desired application ofsealing the respective glass surface to the respective portion of thevehicle 10 (see FIG. 1) and can include various combinations of bodies,legs, lips, flanges, gripping portions, and edges as previouslydescribed in FIGS. 3-4. In some aspects, the static sealing member 12may be extruded around a piece of metal to provide greater structuralstability as shown in outer belt static seal 122, rear pillar staticseal 142, and first center pillar static seal 146. In some aspects, thestatic sealing member 12 may have a flock material coupled to a surfaceof the member 12. The term “flock”, as used herein, is defined to mean apolyester and/or polyamide, used as a coating, extender, and/or fillerwith the dense silane-crosslinked polyolefin elastomer to provide asurface having a lower surface energy and/or lower friction surface.

Thus, the disclosure focuses on the composition, method of making thecomposition, and the corresponding material properties for the densesilane-crosslinked polyolefin elastomer used to make static seals, e.g.,static sealing members 12. The static sealing member 12 is formed from asilane-grafted polyolefin where the silane-grafted polyolefin may have acatalyst added to form a silane-crosslinkable polyolefin elastomer. Thissilane-crosslinkable polyolefin may then be crosslinked upon exposure tomoisture and/or heat to form the final dense silane-crosslinkedpolyolefin elastomer or blend. In aspects, the dense silane-crosslinkedpolyolefin elastomer or blend includes a first polyolefin having adensity less than 0.90 g/cm³, a second polyolefin having a crystallinityof less than 40%, a silane crosslinker, a graft initiator, and acondensation catalyst.

First Polyolefin

The first polyolefin can be a polyolefin elastomer including an olefinblock copolymer, an ethylene/α-olefin copolymer, a propylene/α-olefincopolymer, EPDM, EPM, or a mixture of two or more of any of thesematerials. Exemplary block copolymers include those sold under the tradenames INFUSE™, an olefin block co-polymer (the Dow Chemical Company) andSEPTON™ V-SERIES, a styrene-ethylene-butylene-styrene block copolymer(Kuraray Co., LTD.). Exemplary ethylene/α-olefin copolymers includethose sold under the trade names TAFMER™ (e.g., TAFMER DF710) (MitsuiChemicals, Inc.), and ENGAGE™ (e.g., ENGAGE 8150) (the Dow ChemicalCompany). Exemplary propylene/α-olefin copolymers include those soldunder the trade name VISTAMAXX 6102 grades (Exxon Mobil ChemicalCompany), TAFMER™ XM (Mitsui Chemical Company), and Versify (DowChemical Company). The EPDM may have a diene content of from about 0.5to about 10 wt %. The EPM may have an ethylene content of 45 wt % to 75wt %.

The term “comonomer” refers to olefin comonomers which are suitable forbeing polymerized with olefin monomers, such as ethylene or propylenemonomers. Comonomers may comprise but are not limited to aliphaticC₂-C₂₀ α-olefins. Examples of suitable aliphatic C₂-C₂₀ α-olefinsinclude ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene,1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene,1-octadecene and 1-eicosene. In an embodiment, the comonomer is vinylacetate. The term “copolymer” refers to a polymer, which is made bylinking more than one type of monomer in the same polymer chain. Theterm “homopolymer” refers to a polymer which is made by linking olefinmonomers, in the absence of comonomers. The amount of comonomer can, insome embodiments, be from greater than 0 to about 12 wt % based on theweight of the polyolefin, including from greater than 0 to about 9 wt %and from greater than 0 to about 7 wt %. In some embodiments, thecomonomer content is greater than about 2 mol % of the final polymer,including greater than about 3 mol % and greater than about 6 mol %. Thecomonomer content may be less than or equal to about 30 mol %. Acopolymer can be a random or block (heterophasic) copolymer. In someembodiments, the polyolefin is a random copolymer of propylene andethylene.

In some aspects, the first polyolefin is selected from the groupconsisting of: an olefin homopolymer, a blend of homopolymers, acopolymer made using two or more olefins, a blend of copolymers eachmade using two or more olefins, and a combination of olefin homopolymersblended with copolymers made using two or more olefins. The olefin maybe selected from ethylene, propylene, 1-butene, 1-propene, 1-hexene,1-octene, and other higher 1-olefin. The first polyolefin may besynthesized using many different processes (e.g., using gas phase andsolution based using metallocene catalysis and Ziegler-Natta catalysis)and optionally using a catalyst suitable for polymerizing ethyleneand/or α-olefins. In some aspects, a metallocene catalyst may be used toproduce low density ethylene/α-olefin polymers.

In some aspects, the polyethylene used for the first polyolefin can beclassified into several types including, but not limited to, LDPE (LowDensity Polyethylene), LLDPE (Linear Low Density Polyethylene), and HDPE(High Density Polyethylene). In other aspects, the polyethylene can beclassified as Ultra High Molecular Weight (UHMW), High Molecular Weight(HMW), Medium Molecular Weight (MMW) and Low Molecular Weight (LMW). Instill other aspects, the polyethylene may be an ultra-low densityethylene elastomer.

In some aspects, the first polyolefin may include a LDPE/silanecopolymer or blend. In other aspects, the first polyolefin may bepolyethylene that can be produced using any catalyst known in the artincluding, but not limited to, chromium catalysts, Ziegler-Nattacatalysts, metallocene catalysts or post-metallocene catalysts.

In some aspects, the first polyolefin may have a molecular weightdistribution M_(w)/M_(n) of less than or equal to about 5, less than orequal to about 4, from about 1 to about 3.5, or from about 1 to about 3.

The first polyolefin may be present in an amount of from greater than 0to about 100 wt % of the composition. In some embodiments, the amount ofpolyolefin elastomer is from about 30 to about 70 wt %. In some aspects,the first polyolefin fed to an extruder can include from about 50 wt %to about 80 wt % of an ethylene/α-olefin copolymer, including from about60 wt % to about 75 wt % and from about 62 wt % to about 72 wt %.

The first polyolefin may have a melt viscosity in the range of fromabout 2,000 cP to about 50,000 cP as measured using a Brookfieldviscometer at a temperature of about 177° C. In some embodiments, themelt viscosity is from about 4,000 cP to about 40,000 cP, including fromabout 5,000 cP to about 30,000 cP and from about 6,000 cP to about18,000 cP.

The first polyolefin may have a melt index (T2), measured at 190° C.under a 2.16 kg load, of from about 20.0 g/10 min to about 3,500 g/10min, including from about 250 g/10 min to about 1,900 g/10 min and fromabout 300 g/10 min to about 1,500 g/10 min. In some aspects, the firstpolyolefin has a fractional melt index of from 0.5 g/10 min to about3,500 g/10 min.

In some aspects, the density of the first polyolefin is less than 0.90g/cm³, less than about 0.89 g/cm³, less than about 0.88 g/cm³, less thanabout 0.87 g/cm³, less than about 0.86 g/cm³, less than about 0.85g/cm³, less than about 0.84 g/cm³,. less than about 0.83 g/cm³, lessthan about 0.82 g/cm³, less than about 0.81 g/cm³, or less than about0.80 g/cm³. In other aspects, the density of the first polyolefin may befrom about 0.85 g/cm³to about 0.89 g/cm³, from about 0.85 g/cm³to about0.88 g/cm³, from about 0.84 g/cm³to about 0.88 g/cm³, or from about 0.83g/cm³to about 0.87 g/cm³. In still other aspects, the density is atabout 0.84 g/cm³, about 0.85 g/cm³, about 0.86 g/cm³, about 0.87 g/cm³,about 0.88 g/cm³, or about 0.89 g/cm³.

The percent crystallinity of the first polyolefin may be less than about60%, less than about 50%, less than about 40%, less than about 35%, lessthan about 30%, less than about 25%, or less than about 20%. The percentcrystallinity may be at least about 10%. In some aspects, thecrystallinity is in the range of from about 2% to about 60%.

Second Polyolefin

The second polyolefin can be a polyolefin elastomer including an olefinblock copolymer, an ethylene/α-olefin copolymer, a propylene/α-olefincopolymer, EPDM, EPM, or a mixture of two or more of any of thesematerials. Exemplary block copolymers include those sold under the tradenames INFUSE™ (the Dow Chemical Company) and SEPTON™ V-SERIES (KurarayCo., LTD.). Exemplary ethylene/α-olefin copolymers include those soldunder the trade names TAFMER™ (e.g., TAFMER DF710) (Mitsui Chemicals,Inc.) and ENGAGE™ (e.g., ENGAGE 8150) (the Dow Chemical Company).Exemplary propylene/α-olefin copolymers include those sold under thetrade name TAFMER™ XM grades (Mitsui Chemical Company) and VISTAMAXX™(e.g., VISTAMAXX 6102) (Exxon Mobil Chemical Company),. The EPDM mayhave a diene content of from about 0.5 to about 10 wt %. The EPM mayhave an ethylene content of 45 wt % to 75 wt %.

In some aspects, the second polyolefin is selected from the groupconsisting of: an olefin homopolymer, a blend of homopolymers, acopolymer made using two or more olefins, a blend of copolymers eachmade using two or more olefins, and a blend of olefin homopolymers withcopolymers made using two or more olefins. The olefin may be selectedfrom ethylene, propylene, 1-butene, 1-propene, 1-hexene, 1-octene, andother higher 1-olefin. The first polyolefin may be synthesized usingmany different processes (e.g., using gas phase and solution based usingmetallocene catalysis and Ziegler-Natta catalysis) and optionally usinga catalyst suitable for polymerizing ethylene and/or α-olefins. In someaspects, a metallocene catalyst may be used to produce low densityethylene/α-olefin polymers.

In some aspects, the second polyolefin may include a polypropylenehomopolymer, a polypropylene copolymer, a polyethylene-co-propylenecopolymer, or a mixture thereof. Suitable polypropylenes include but arenot limited to polypropylene obtained by homopolymerization of propyleneor copolymerization of propylene and an alphα-olefin comonomer. In someaspects, the second polyolefin may have a higher molecular weight and/ora higher density than the first polyolefin.

In some embodiments, the second polyolefin may have a molecular weightdistribution M_(w)/M_(n) of less than or equal to about 5, less than orequal to about 4, from about 1 to about 3.5, or from about 1 to about 3.

The second polyolefin may be present in an amount of from greater than 0wt % to about 100 wt % of the composition. In some embodiments, theamount of polyolefin elastomer is from about 30 wt % to about 70 wt %.In some embodiments, the second polyolefin fed to the extruder caninclude from about 10 wt % to about 50 wt % polypropylene, from about 20wt % to about 40 wt % polypropylene, or from about 25 wt % to about 35wt % polypropylene. The polypropylene may be a homopolymer or acopolymer.

The second polyolefin may have a melt viscosity in the range of fromabout 2,000 cP to about 50,000 cP as measured using a Brookfieldviscometer at a temperature of about 177° C. In some embodiments, themelt viscosity is from about 4,000 cP to about 40,000 cP, including fromabout 5,000 cP to about 30,000 cP and from about 6,000 cP to about18,000 cP.

The second polyolefin may have a melt index (T2), measured at 190° C.under a 2.16 kg load, of from about 20.0 g/10 min to about 3,500 g/10min, including from about 250 g/10 min to about 1,900 g/10 min and fromabout 300 g/10 min to about 1,500 g/10 min. In some embodiments, thepolyolefin has a fractional melt index of from 0.5 g/10 min to about3,500 g/10 min.

In some aspects, the density of the second polyolefin is less than 0.90g/cm³, less than about 0.89 g/cm³, less than about 0.88 g/cm³, less thanabout 0.87 g/cm³, less than about 0.86 g/cm³, less than about 0.85g/cm³, less than about 0.84 g/cm³,. less than about 0.83 g/cm³, lessthan about 0.82 g/cm³, less than about 0.81 g/cm³, or less than about0.80 g/cm³. In other aspects, the density of the first polyolefin may befrom about 0.85 g/cm³to about 0.89 g/cm³, from about 0.85 g/cm³to about0.88 g/cm³, from about 0.84 g/cm³to about 0.88 g/cm³, or from about 0.83g/cm³to about 0.87 g/cm³. In still other aspects, the density is atabout 0.84 g/cm³, about 0.85 g/cm³, about 0.86 g/cm³, about 0.87 g/cm³,about 0.88 g/cm³, or about 0.89 g/cm³.

The percent crystallinity of the second polyolefin may be less thanabout 60%, less than about 50%, less than about 40%, less than about35%, less than about 30%, less than about 25%, or less than about 20%.The percent crystallinity may be at least about 10%. In some aspects,the crystallinity is in the range of from about 2% to about 60%.

As noted, the silane-crosslinked polyolefin elastomer or blend, e.g., asemployed in static sealing members 12 (see FIGS. 1, 2, 4 and 5),includes both the first polyolefin and the second polyolefin. The secondpolyolefin is generally used to modify the hardness and/orprocessability of the first polyolefin having a density less than 0.90g/cm³. In some aspects, more than just the first and second polyolefinsmay be used to form the silane-crosslinked polyolefin elastomer orblend. For example, in some aspects, one, two, three, four, or moredifferent polyolefins having a density less than 0.90 g/cm³, less than0.89 g/cm³, less than 0.88 g/cm³, less than 0.87 g/cm³, less than 0.86g/cm³, or less than 0.85 g/cm³ may be substituted and/or used for thefirst polyolefin. In some aspects, one, two, three, four, or moredifferent polyolefins, polyethylene-co-propylene copolymers may besubstituted and/or used for the second polyolefin.

The blend of the first polyolefin having a density less than 0.90 g/cm³and the second polyolefin having a crystallinity less than 40% is usedbecause the subsequent silane grafting and crosslinking of these firstand second polyolefin materials together are what form the core resinstructure in the final silane-crosslinked polyolefin elastomer. Althoughadditional polyolefins may be added to the blend of the silane-grafted,silane-crosslinkable, and/or silane-crosslinked polyolefin elastomer asfillers to improve and/or modify the Young's modulus as desired for thefinal product, any polyolefins added to the blend having a crystallinityequal to or greater than 40% are not chemically or covalentlyincorporated into the crosslinked structure of the finalsilane-crosslinked polyolefin elastomer.

In some aspects, the first and second polyolefins may further includeone or more TPVs and/or EPDM with or without silane graft moieties wherethe TPV and/or EPDM polymers are present in an amount of up to 20 wt %of the silane-crosslinker polyolefin elastomer/blend.

Grafting Initiator

A grafting initiator (also referred to as “a radical initiator” in thedisclosure) can be utilized in the grafting process of at least thefirst and second polyolefins by reacting with the respective polyolefinsto form a reactive species that can react and/or couple with the silanecrosslinker molecule. The grafting initiator can include halogenmolecules, azo compounds (e.g., azobisisobutyl), carboxylic peroxyacids,peroxyesters, peroxyketals, and peroxides (e.g., alkyl hydroperoxides,dialkyl peroxides, and diacyl peroxides). In some embodiments, thegrafting initiator is an organic peroxide selected from di-t-butylperoxide, t-butyl cumyl peroxide, dicumyl peroxide,2,5-dimethyl-2,5-di(t-butyl-peroxy)hexyne-3,1,3-bis(t-butyl-peroxy-isopropyl)benzene,n-butyl-4,4-bis(t-butyl-peroxy)valerate, benzoyl peroxide,t-butylperoxybenzoate, t-butylperoxy isopropyl carbonate, andt-butylperbenzoate, as well as bis(2-methylbenzoyl)peroxide,bis(4-methylbenzoyl)peroxide, t-butyl peroctoate, cumene hydroperoxide,methyl ethyl ketone peroxide, lauryl peroxide, tert-butyl peracetate,di-t-amyl peroxide, t-amyl peroxybenzoate,1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane,α,α′-bis(t-butylperoxy)-1,3-diisopropylbenzene,α,α′-bis(t-butylpexoxy)-1,4-diisopropylbenzene,2,5-bis(t-butylperoxy)-2,5-dimethylhexane, and2,5-bis(t-butylperoxy)-2,5-dimethyl-3-hexyne and 2,4-dichlorobenzoylperoxide. Exemplary peroxides include those sold under the tradenameLUPEROX™ (available from Arkema, Inc.).

In some aspects, the grafting initiator is present in an amount of fromgreater than 0 wt % to about 2 wt % of the composition, including fromabout 0.15 wt % to about 1.2 wt % of the composition. The amount ofinitiator and silane employed may affect the final structure of thesilane grafted polymer (e.g., the degree of grafting in the graftedpolymer and the degree of crosslinking in the cured polymer). In someaspects, the reactive composition contains at least 100 ppm ofinitiator, or at least 300 ppm of initiator. The initiator may bepresent in an amount from 300 ppm to 1500 ppm, or from 300 ppm to 2000ppm. The silane:initiator weight ratio may be from about 20:1 to 400:1,including from about 30:1 to about 400:1, from about 48:1 to about350:1, and from about 55:1 to about 333:1.

The grafting reaction can be performed under conditions that optimizegrafts onto the interpolymer backbone while minimizing side reactions(e.g., the homopolymerization of the grafting agent). The graftingreaction may be performed in a melt, in solution, in a solid-state,and/or in a swollen-state. The silanation may be performed in awide-variety of equipment (e.g., twin screw extruders, single screwextruders, Brabenders, internal mixers such as Banbury mixers, and batchreactors). In some embodiments, the polyolefin, silane, and initiatorare mixed in the first stage of an extruder. The melt temperature (i.e.,the temperature at which the polymer starts melting and starts to flow)may be from about 120° C. to about 260° C., including from about 130° C.to about 250° C.

Silane Crosslinker

A silane crosslinker can be used to covalently graft silane moietiesonto the first and second polyolefins and the silane crosslinker mayinclude alkoxysilanes, silazanes, siloxanes, or a combination thereof.The grafting and/or coupling of the various potential silanecrosslinkers or silane crosslinker molecules is facilitated by thereactive species formed by the grafting initiator reacting with therespective silane crosslinker.

In some aspects, the silane crosslinker is a silazane where the silazanemay include, for example, hexamethyldisilazane (HMDS) orBis(trimethylsilyl)amine. In some aspects, the silane crosslinker is asiloxane where the siloxane may include, for example,polydimethylsiloxane (PDMS) and octamethylcyclotetrasiloxane.

In some aspects, the silane crosslinker is an alkoxysilane. As usedherein, the term “alkoxysilane” refers to a compound that comprises asilicon atom, at least one alkoxy group and at least one other organicgroup, wherein the silicon atom is bonded with the organic group by acovalent bond. Preferably, the alkoxysilane is selected fromalkylsilanes; acryl-based silanes; vinyl-based silanes; aromaticsilanes; epoxy-based silanes; amino-based silanes and amines thatpossess —NH₂, —NHCH₃ or —N(CH₃)₂; ureide-based silanes; mercapto-basedsilanes; and alkoxysilanes which have a hydroxyl group (i.e., —OH). Anacryl-based silane may be selected from the group comprisingbeta-acryloxyethyl trimethoxysilane; beta-acryloxy propyltrimethoxysilane; gamma-acryloxyethyl trimethoxysilane;gamma-acryloxypropyl trimethoxysilane; beta-acryloxyethyltriethoxysilane; beta-acryloxypropyl triethoxysilane;gamma-acryloxyethyl triethoxysilane; gamma-acryloxypropyltriethoxysilane; beta-methacryloxyethyl trimethoxysilane;beta-methacryloxypropyl trimethoxysilane; gamma-methacryloxyethyltrimethoxysilane; gamma-methacryloxypropyl trimethoxysilane;beta-methacryloxyethyl triethoxysilane; beta-methacryloxypropyltriethoxysilane; gamma-methacryloxyethyl triethoxysilane;gamma-methacryloxypropyl triethoxysilane; 3-methacryloxypropylmethyldiethoxysilane. A vinyl-based silane may be selected from the groupcomprising vinyl trimethoxysilane; vinyl triethoxysilane; p-styryltrimethoxysilane, methylvinyldimethoxysilane,vinyldimethylmethoxysilane, divinyldimethoxysilane,vinyltris(2-methoxyethoxy)silane, andvinylbenzylethylenediaminopropyltrimethoxysilane. An aromatic silane maybe selected from phenyltrimethoxysilane and phenyltriethoxysilane. Anepoxy-based silane may be selected from the group comprising3-glycydoxypropyl trimethoxysilane; 3-glycydoxypropylmethyldiethoxysilane; 3-glycydoxypropyl triethoxysilane;2-(3,4-epoxycyclohexyl)ethyl trimethoxysilane, andglycidyloxypropylmethyldimethoxysilane. An amino-based silane may beselected from the group comprising 3-aminopropyl triethoxysilane;3-aminopropyl trimethoxysilane; 3-aminopropyldimethyl ethoxysilane;3-aminopropylmethyldiethoxysilane; 4-aminobutyltriethoxysilane;3-aminopropyldiisopropyl ethoxysilane;1-amino-2-(dimethylethoxysilyl)propane;(aminoethylamino)-3-isobutyldimethyl methoxysilane;N-(2-aminoethyl)-3-aminoisobutylmethyl dimethoxysilane;(aminoethylaminomethyl)phenetyl trimethoxysilane;N-(2-aminoethyl)-3-aminopropylmethyl dimethoxysilane;N-(2-aminoethyl)-3-aminopropyl trimethoxysilane;N-(2-aminoethyl)-3-aminopropyl triethoxysilane;N-(6-aminohexyl)aminomethyl trimethoxysilane;N-(6-aminohexyl)aminomethyl trimethoxysilane;N-(6-aminohexyl)aminopropyl trimethoxysilane;N-(2-aminoethyl)-1,1-aminoundecyl trimethoxysilane; 1,1-aminoundecyltriethoxysilane; 3-(m-aminophenoxy)propyl trimethoxysilane;m-aminophenyl trimethoxysilane; p-aminophenyl trimethoxysilane;(3-trimethoxysilylpropyl)diethylenetriamine; N-methylaminopropylmethyldimethoxysilane; N-methylaminopropyl trimethoxysilane;dimethylaminomethyl ethoxysilane;(N,N-dimethylaminopropyl)trimethoxysilane;(N-acetylglycysil)-3-aminopropyl trimethoxysilane,N-phenyl-3-aminopropyltrimethoxysilane,N-phenyl-3-aminopropyltriethoxysilane,phenylaminopropyltrimethoxysilane,aminoethylaminopropyltrimethoxysilane, andaminoethylaminopropylmethyldimethoxysilane. An ureide-based silane maybe 3-ureidepropyl triethoxysilane. A mercapto-based silane may beselected from the group comprising 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyl trimethoxysilane, and 3-mercaptopropyltriethoxysilane. An alkoxysilane having a hydroxyl group may be selectedfrom the group comprising hydroxymethyl triethoxysilane;N-(hydroxyethyl)-N-methylaminopropyl trimethoxysilane;bis(2-hydroxyethyl)-3-aminopropyl triethoxysilane;N-(3-triethoxysilylpropyl)-4-hydroxy butylamide;1,1-(triethoxysilyl)undecanol; triethoxysilyl undecanol; ethylene glycolacetal; and N-(3-ethoxysilylpropyl)gluconamide.

In some aspects, the alkylsilane may be expressed with a generalformula: R_(n)Si(OR′)_(4-n) wherein: n is 1, 2 or 3; R is a C₁₋₂₀alkylor a C₂₋₂₀alkenyl; and R′ is an C₁₋₂₀alkyl. The term “alkyl” by itselfor as part of another substituent, refers to a straight, branched orcyclic saturated hydrocarbon group joined by single carbon-carbon bondshaving 1 to 20 carbon atoms, for example 1 to 10 carbon atoms, forexample 1 to 8 carbon atoms, preferably 1 to 6 carbon atoms. When asubscript is used herein following a carbon atom, the subscript refersto the number of carbon atoms that the named group may contain. Thus,for example, C₁₋₆alkyl means an alkyl of one to six carbon atoms.Examples of alkyl groups are methyl, ethyl, propyl, isopropyl, butyl,isobutyl, sec-butyl, f-butyl, 2-methylbutyl, pentyl, iso-amyl and itsisomers, hexyl and its isomers, heptyl and its isomers, octyl and itsisomer, decyl and its isomer, dodecyl and its isomers. The term“C₂₋₂₀alkenyl” by itself or as part of another substituent, refers to anunsaturated hydrocarbyl group, which may be linear, or branched,comprising one or more carbon-carbon double bonds having 2 to 20 carbonatoms. Examples of C₂₋₆alkenyl groups are ethenyl, 2-propenyl,2-butenyl, 3-butenyl, 2-pentenyl and its isomers, 2-hexenyl and itsisomers, 2,4-pentadienyl and the like.

In some aspects, the alkylsilane may be selected from the groupcomprising methyltrimethoxysilane; methyltriethoxysilane;ethyltrimethoxysilane; ethyltriethoxysilane; propyltrimethoxysilane;propyltriethoxysilane; hexyltrimethoxysilane; hexyltriethoxysilane;octyltrimethoxysilane; octyltriethoxysilane; decyltrimethoxysilane;decyltriethoxysilane; dodecyltrimethoxysilane: dodecyltriethoxysilane;tridecyltrimethoxysilane; dodecyltriethoxysilane;hexadecyltrimethoxysilane; hexadecyltriethoxysilane;octadecyltrimethoxysilane; octadecyltriethoxysilane,trimethylmethoxysilane, methylhydrodimethoxysilane,dimethyldimethoxysilane, diisopropyldimethoxysilane,diisobutyldimethoxysilane, isobutyltrimethoxysilane,n-butyltrimethoxysilane, n-butylmethyldimethoxysilane,phenyltrimethoxysilane, phenyltrimethoxysilane,phenylmethyldimethoxysilane, triphenylsilanol, n-hexyltrimethoxysilane,n-octyltrimethoxysilane, isooctyltrimethoxysilane,decyltrimethoxysilane, hexadecyltrimethoxysilane,cyclohexylmethyldimethoxysilane, cyclohexylethyldimethoxysilane,dicyclopentyldimethoxysilane, tert-butylethyldimethoxysilane,tert-butylpropyldimethoxysilane, dicyclohexyldimethoxysilane, and acombination thereof.

In some aspects, the alkylsilane compound may be selected fromtriethoxyoctylsilane, trimethoxyoctylsilane, and a combination thereof.

Additional examples of silanes that can be used as silane crosslinkersinclude, but are not limited to, those of the general formulaCH₂═CR—(COO)_(x)(C_(n)H_(2n))_(y)SiR′₃, wherein R is a hydrogen atom ormethyl group; x is 0 or 1; y is 0 or 1; n is an integer from 1 to 12;each R′ can be an organic group and may be independently selected froman alkoxy group having from 1 to 12 carbon atoms (e.g., methoxy, ethoxy,butoxy), aryloxy group (e.g., phenoxy), araloxy group (e.g., benzyloxy),aliphatic acyloxy group having from 1 to 12 carbon atoms (e.g.,formyloxy, acetyloxy, propanoyloxy), amino or substituted amino groups(e.g., alkylamino, arylamino), or a lower alkyl group having 1 to 6carbon atoms. x and y may both equal 1. In some aspects, no more thanone of the three R′ groups is an alkyl. In other aspects, not more thantwo of the three R′ groups is an alkyl.

Any silane or mixture of silanes known in the art that can effectivelygraft to and crosslink an olefin polymer can be used in the practice ofthe present disclosure. In some aspects, the silane crosslinker caninclude, but is not limited to, unsaturated silanes which include anethylenically unsaturated hydrocarbyl group (e.g., a vinyl, allyl,isopropenyl, butenyl, cyclohexenyl or a gamma-(meth)acryloxy allylgroup) and a hydrolyzable group (e.g., a hydrocarbyloxy,hydrocarbonyloxy, or hydrocarbylamino group). Non-limiting examples ofhydrolyzable groups include, but are not limited to, methoxy, ethoxy,formyloxy, acetoxy, proprionyloxy, and alkyl, or arylamino groups. Inother aspects, the silane crosslinkers are unsaturated alkoxy silaneswhich can be grafted onto the polymer. In still other aspects,additional exemplary silane crosslinkers include vinyltrimethoxysilane,vinyltriethoxysilane, 3-(trimethoxysilyl)propyl methacrylategamma-(meth)acryloxypropyl trimethoxysilane), and mixtures thereof.

The silane crosslinker may be present in the silane-grafted polyolefinelastomer in an amount of from greater than 0 wt % to about 10 wt %,including from about 0.5 wt % to about 5 wt %. The amount of silanecrosslinker may be varied based on the nature of the olefin polymer, thesilane itself, the processing conditions, the grafting efficiency, theapplication, and other factors. The amount of silane crosslinker may beat least 2 wt %, including at least 4 wt % or at least 5 wt %, based onthe weight of the reactive composition. In other aspects, the amount ofsilane crosslinker may be at least 10 wt %, based on the weight of thereactive composition. In still other aspects, the silane crosslinkercontent is at least 1% based on the weight of the reactive composition.In some embodiments, the silane crosslinker fed to the extruder mayinclude from about 0.5 wt % to about 10 wt % of silane monomer, fromabout 1 wt % to about 5 wt % silane monomer, or from about 2 wt % toabout 4 wt % silane monomer.

Condensation Catalyst

A condensation catalyst can facilitate both the hydrolysis andsubsequent condensation of the silane grafts on the silane-graftedpolyolefin elastomer to form crosslinks. In some aspects, thecrosslinking can be aided by the use of an electron beam radiation. Insome aspects, the condensation catalyst can include, for example,organic bases, carboxylic acids, and organometallic compounds (e.g.,organic titanates and complexes or carboxylates of lead, cobalt, iron,nickel, zinc, and tin). In other aspects, the condensation catalyst caninclude fatty acids and metal complex compounds such as metalcarboxylates; aluminum triacetyl acetonate, iron triacetyl acetonate,manganese tetraacetyl acetonate, nickel tetraacetyl acetonate, chromiumhexaacetyl acetonate, titanium tetraacetyl acetonate and cobalttetraacetyl acetonate; metal alkoxides such as aluminum ethoxide,aluminum propoxide, aluminum butoxide, titanium ethoxide, titaniumpropoxide and titanium butoxide; metal salt compounds such as sodiumacetate, tin octylate, lead octylate, cobalt octylate, zinc octylate,calcium octylate, lead naphthenate, cobalt naphthenate, dibutyltindioctoate, dibutyltin dilaurate, dibutyltin maleate and dibutyltindi(2-ethylhexanoate); acidic compounds such as formic acid, acetic acid,propionic acid, p-toluenesulfonic acid, trichloroacetic acid, phosphoricacid, monoalkylphosphoric acid, dialkylphosphoric acid, phosphate esterof p-hydroxyethyl (meth)acrylate, monoalkylphosphorous acid anddialkylphosphorous acid; acids such as p-toluenesulfonic acid, phthalicanhydride, benzoic acid, benzenesulfonic acid, dodecylbenzenesulfonicacid, formic acid, acetic acid, itaconic acid, oxalic acid and maleicacid, ammonium salts, lower amine salts or polyvalent metal salts ofthese acids, sodium hydroxide, lithium chloride; organometal compoundssuch as diethyl zinc and tetra(n-butoxy)titanium; and amines such asdicyclohexylamine, triethylamine, N,N-dimethylbenzylamine,N,N,N′,N′-tetramethyl-1 ,3-butanediamine, diethanolamine,triethanolamine and cyclohexylethylamine. In still other aspects, thecondensation catalyst can include ibutyltindilaurate, dioctyltinmaleate,dibutyltindiacetate, dibutyltindioctoate, stannous acetate, stannousoctoate, lead naphthenate, zinc caprylate, and cobalt naphthenate.Depending on the desired final material properties of thesilane-crosslinked polyolefin elastomer or blend, a single condensationcatalyst or a mixture of condensation catalysts may be utilized. Thecondensation catalyst(s) may be present in an amount of from about 0.01wt % to about 1.0 wt5, including from about 0.25 wt % to about 8 wt %,based on the total weight of the silane-grafted polyolefinelastomer/blend composition.

In some aspects, a crosslinking system can include and use one or all ofa combination of radiation, heat, moisture, and additional condensationcatalyst. In some aspects, the condensation catalyst may be present inan amount of from 0.25 wt % to 8 wt %. In other aspects, thecondensation catalyst may be included in an amount of from about 1 wt %to about 10 wt %, or from about 2 wt % to about 5 wt %.

Optional Additional Components

The silane-crosslinked polyolefin elastomer may optionally include oneor more fillers.

The filler(s) may be extruded with the silane-grafted polyolefin and insome aspects may include additional polyolefins having a crystallinitygreater than 20%, greater than 30%, greater than 40%, or greater than50%. In some aspects, the filler(s) may include metal oxides, metalhydroxides, metal carbonates, metal sulfates, metal silicates, clays,talcs, carbon black, and silicas. Depending on the application and/ordesired properties, these materials may be fumed or calcined.

The metal of the metal oxide, metal hydroxide, metal carbonate, metalsulfate, or metal silicate may be selected from alkali metals (e.g.,lithium, sodium, potassium, rubidium, caesium, and francium); alkalineearth metals (e.g., beryllium, magnesium, calcium, strontium, barium,and radium); transition metals (e.g., zinc, molybdenum, cadmium,scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel,copper, yttrium, zirconium, niobium, technetium, ruthernium, rhodium,palladium, silver, hafnium, taltalum, tungsten, rhenium, osmium, indium,platinum, gold, mercury, rutherfordium, dubnium, seaborgium, bohrium,hassium, and copernicium); post-transition metals (e.g., aluminum,gallium, indium, tin, thallium, lead, bismuth, and polonium);lanthanides (e.g., lanthanum, cerium, praseodymium, neodymium,promethium, samarium, europium, gadolinium, terbium, dysprosium,holmium, erbium, thulium, ytterbium, and lutetium); actinides (e.g.,actinium, thorium, protactinium, uranium, neptunium, plutonium,americium, curium, berkelium, californium, einsteinium, fermium,mendelevium, nobelium, and lawrencium); germanium; arsenic; antimony;and astatine.

The filler(s) of the silane-crosslinked polyolefin elastomer or blendmay be present in an amount of from greater than 0 wt % to about 50 wt%, including from about 1 wt % to about 20 wt % and from about 3 wt % toabout 10 wt %.

The silane-crosslinked polyolefin elastomer and/or the respectivearticles formed (e.g., static sealing members 12) may also include waxes(e.g., paraffin waxes, microcrystalline waxes, HDPE waxes, LDPE waxes,thermally degraded waxes, byproduct polyethylene waxes, optionallyoxidized Fischer-Tropsch waxes, and functionalized waxes). In someembodiments, the wax(es) are present in an amount of from about 0 wt %to about 10 wt %.

Tackifying resins (e.g., aliphatic hydrocarbons, aromatic hydrocarbons,modified hydrocarbons, terpens, modified terpenes, hydrogenatedterpenes, rosins, rosin derivatives, hydrogenated rosins, and mixturesthereof) may also be included in the silane-crosslinked polyolefinelastomer/blend. The tackifying resins may have a ring and ballsoftening point in the range of from 70° C. to about 150° C. and aviscosity of less than about 3,000 cP at 177° C. In some aspects, thetackifying resin(s) are present in an amount of from about 0 wt % toabout 10 wt %.

In some aspects, the silane-crosslinked polyolefin elastomer may includeone or more oils. Non-limiting types of oils include white mineral oilsand naphthenic oils. In some embodiments, the oil(s) are present in anamount of from about 0 wt % to about 10 wt %.

In some aspects, the silane-crosslinked polyolefin elastomer may includeone or more filler polyolefins having a crystallinity greater than 20%,greater than 30%, greater than 40%, or greater than 50%. The fillerpolyolefin may include polypropylene, poly(ethylene-co-propylene),and/or other ethylene/α-olefin copolymers. In some aspects, the use ofthe filler polyolefin may be present in an amount of from about 5 wt %to about 60 wt %, from about 10 wt % to about 50 wt %, from about 20 wt% to about 40 wt %, or from about 5 wt % to about 20 wt %. The additionof the filler polyolefin may increase the Young's modulus by at least10%, by at least 25%, or by at least 50% for the finalsilane-crosslinked polyolefin elastomer.

In some aspects, the silane-crosslinked polyolefin elastomer of thepresent disclosure may include one or more stabilizers (e.g.,antioxidants). The silane-crosslinked polyolefin elastomer may betreated before grafting, after grafting, before crosslinking, and/orafter crosslinking. Other additives may also be included. Non-limitingexamples of additives include antistatic agents, dyes, pigments, UVlight absorbers, nucleating agents, fillers, slip agents, plasticizers,fire retardants, lubricants, processing aides, smoke inhibitors,anti-blocking agents, and viscosity control agents. The antioxidant(s)may be present in an amount of less than 0.5 wt %, including less than0.2 wt % of the composition.

Method for Making the Silane-Grafted Polyolefin Elastomer

The synthesis/production of the dense silane-crosslinked polyolefinelastomer may be performed by combining the respective components in oneextruder using a single-step Monosil process or in two extruders using atwo-step Sioplas process which eliminates the need for additional stepsof mixing and shipping rubber compounds prior to extrusion.

Referring now to FIG. 7, the general chemical process used during boththe single-step

Monosil process and two-step Sioplas process used to synthesize thedense silane-crosslinked polyolefin elastomer is provided. The processstarts with a grafting step that includes initiation from a graftinginitiator followed by propagation and chain transfer with the first andsecond polyolefins. The grafting initiator, in some aspects a peroxideor azo compound, homolytically cleaves to form two radical initiatorfragments that transfer to one of the first and second polyolefinschains through a propagation step. The free radical, now positioned onthe first or second polyolefin chain, can then transfer to a silanemolecule and/or another polyolefin chain. Once the initiator and freeradicals are consumed, the silane grafting reaction for the first andsecond polyolefins is complete.

Still referring to FIG. 7, once the silane grafting reaction iscomplete, a mixture of stable first and second silane-graftedpolyolefins is produced. A crosslinking catalyst may then be added tothe first and second silane-grafted polyolefins to form thesilane-grafted polyolefin elastomer. The crosslinking catalyst may firstfacilitate the hydrolysis of the silyl group grafted onto the polyolefinbackbones to form reactive silanol groups. The silanol groups may thenreact with other silanol groups on other polyolefin molecules to form acrosslinked network of elastomeric polyolefin polymer chains linkedtogether through siloxane linkages. The density of silane crosslinksthroughout the silane-grafted polyolefin elastomer can influence thematerial properties exhibited by the elastomer.

Referring now to FIGS. 8 and 9A, a method 300 for making a static seal,such as the static sealing member 12, using the two-step Sioplas processis shown. The method 300 may begin with a step 304 that includesextruding (e.g., with a twin screw extruder 182) the first polyolefin170 having a density less than 0.86 g/cm³, the second polyolefin 174,and a silan cocktail 178 including the silane crosslinker (e.g.,vinyltrimethoxy silane, VTMO) and the grafting initiator (e.g. dicumylperoxide) together to form a silane-grafted polyolefin blend. The firstpolyolefin 170 and second polyolefin 174 may be added to a reactive twinscrew extruder 182 using an addition hopper 186. The silan cocktail 178may be added to the twin screws 190 further down the extrusion line tohelp promote better mixing with the first and second polyolefin 170, 174blend. A forced volatile organic compound (VOC) vacuum 194 may be usedon the reactive twin screw extruder 182 to help maintain a desiredreaction pressure. The twin screw extruder 182 is considered reactivebecause the radical initiator and silane crosslinker are reacting withand forming new covalent bonds with both the first and secondpolyolefins 170, 174. The melted silane-grafted polyolefin blend canexit the reactive twin screw extruder 182 using a gear pump 198 thatinjects the molten silane-grafted polyolefin blend into a waterpelletizer 202 that can form a pelletized silane-grafted polyolefinblend 206. In some aspects, the molten silane-grafted polyolefin blendmay be extruded into pellets, pillows, or any other configuration priorto the incorporation of the condensation catalyst 210 (see FIG. 9B) andformation of the final article.

The reactive twin screw extruder 182 can be configured to have aplurality of different temperature zones (e.g., Z0-Z12 as shown in FIG.9A) that extend for various lengths of the twin screw extruder 182. Insome aspects, the respective temperature zones may have temperaturesranging from about room temperature to about 180° C., from about 120° C.to about 170° C., from about 120° C. to about 160° C., from about 120°C. to about 150° C., from about 120° C. to about 140° C., from about120° C. to about 130° C., from about 130° C. to about 170° C., fromabout 130° C. to about 160° C., from about 130° C. to about 150° C.,from about 130° C. to about 140° C., from about 140° C. to about 170°C., from about 140° C. to about 160° C., from about 140° C. to about150° C., from about 150° C. to about 170° C., and from about 150° C. toabout 160° C. In some aspects, ZO may have a temperature from about 60°C. to about 110° C. or no cooling; Z1 may have a temperature from about120° C. to about 130° C.; Z2 may have a temperature from about 140° C.to about 150° C.; Z3 may have a temperature from about 150° C. to about160° C.; Z4 may have a temperature from about 150° C. to about 160° C.;Z5 may have a temperature from about 150° C. to about 160° C.; Z6 mayhave a temperature from about 150° C. to about 160° C.; and Z7 may havea temperature from about 150° C. to about 160° C.

In some aspects, the number average molecular weight of thesilane-grafted polyolefin elastomers may be in the range of from about4,000 g/mol to about 30,000 g/mol, including from about 5,000 g/mol toabout 25,000 g/mol and from about 6,000 g/mol to about 14,000 g/mol. Theweight average molecular weight of the grafted polymers may be fromabout 8,000 g/mol to about 60,000 g/mol, including from about 10,000g/mol to about 30,000 g/mol.

Referring now to FIGS. 8 and 9B, the method 300 next includes a step 308of extruding the silane-grafted polyolefin blend 206 and thecondensation catalyst 210 together to form a silane-crosslinkablepolyolefin blend 212. In some aspects, one or more optional additives214 may be added with the silane-grafted polyolefin blend 206 and thecondensation catalyst 210 to adjust the final material properties of thesilane-crosslinked polyolefin olefin blend. In step 308, thesilane-grafted polyolefin blend 206 is mixed with a silanol formingcondensation catalyst 210 to form reactive silanol groups on the silanegrafts that can subsequently crosslink when exposed to humidity and/orheat. In some aspects, the condensation catalyst is AMBICAT™ LE4472 andcan include a mixture of sulfonic acid, antioxidant, process aide, andcarbon black for coloring where the ambient moisture is sufficient forthis condensation catalyst to crosslink the silane-crosslinkablepolyolefin blend over a longer time period (e.g., about 48 hours). Thesilane-grafted polyolefin blend 206 and the condensation catalyst 210may be added to a reactive single screw extruder 218 using an additionhopper and an addition gear pump 226. The combination of thesilane-grafted polyolefin blend 206 and the condensation catalyst 210,and in some aspects one or more optional additives 214, may be added toa single screw 222 of the reactive single screw extruder 218. The singlescrew extruder 218 is considered reactive because crosslinking can beginas soon as the silane-grafted polyolefin blend 206 and the condensationcatalyst 210 are melted and combined together to mix the condensationcatalyst 210 thoroughly and evenly throughout the melted silane-graftedpolyolefin blend 206. The melted silane-crosslinkable polyolefin blend212 can exit the reactive single screw extruder 218 through a die thatcan inject the molten silane-crosslinkable polyolefin blend into anuncured static sealing element.

During step 308, as the silane-grafted polyolefin blend 206 is extrudedtogether with the condensation catalyst 210 to form thesilane-crosslinkable polyolefin blend 212, a certain amount ofcrosslinking may occur. In some aspects, the silane-crosslinkablepolyolefin blend 212 may be about 25% cured, about 30% cured, about 35%cured, about 40% cured, about 45% cured, about 50% cured, about 55%cured, about 60% cured, bout 65% cured, or about 70% cured where geltest (ASTM D2765) can be used to determine the amount of crosslinking inthe final dense silane-crosslinked polyolefin elastomer.

Still referring to FIGS. 8 and 9B, the method 300 further includes astep 312 of molding the silane-crosslinkable polyolefin blend 212 intothe uncured static sealing element. The single screw extruder 218 meltsand extrudes the silane-crosslinkable polyolefin through a die that canextrude the molten silane-crosslinkable polyolefin blend 212 into theuncured static sealing element, for example, uncured or partially curedversions static sealing members 12 such as the inner belt static seal134, front pillar static seal 138, and rear pillar static seal 142.

Referring again to FIG. 8, the method 300 can further include a step 316of crosslinking the silane-crosslinkable polyolefin blend 212 or thestatic sealing member 12 in an uncured form at an ambient temperatureand/or an ambient humidity to form the static sealing member 12 (seeFIGS. 1 and 2) having a density from about 0.85 g/cm³ to about 0.89g/cm³. More particularly, in this crosslinking process, the waterhydrolyzes the silane of the silane-crosslinkable polyolefin elastomerto produce a silanol. The silanol groups on various silane grafts canthen be condensed to form intermolecular, irreversible Si—O—Si crosslinksites. The amount of crosslinked silane groups, and thus the finalpolymer properties, can be regulated by controlling the productionprocess, including the amount of catalyst used.

The crosslinking/curing of step 316 of the method 300 may occur over atime period of from greater than 0 to about 20 hours. In some aspects,curing takes place over a time period of from about 1 hour to about 20hours, 10 hours to about 20 hours, from about 15 hours to about 20hours, from about 5 hours to about 15 hours, from about 1 hour to about8 hours, or from about 3 hours to about 6 hours. The temperature duringthe crosslinking/curing may be about room temperature, from about 20° C.to about 25° C., from about 20° C. to about 150° C., from about 25° C.to about 100° C., or from about 20° C. to about 75° C. The humidityduring curing may be from about 30% to about 100%, from about 40% toabout 100%, or from about 50% to about 100%.

In some aspects, an extruder setting is used that is capable ofextruding thermoplastic, with long L/D, 30 to 1, at an extruder heatsetting close to TPV processing conditions wherein the extrudatecrosslinks at ambient conditions becoming a thermoset in properties. Inother aspects, this process may be accelerated by steam exposure.Immediately after extrusion, the gel content (also called the crosslinkdensity) may be about 60%, but after 96 hrs at ambient conditions, thegel content may reach greater than about 95%.

In some aspects, one or more reactive single screw extruders 218 may beused to form the uncured sealing element and corresponding staticsealing member that have one or more types of silane-crosslinkedpolyolefin elastomers. For example, in some aspects, one reactive singlescrew extruder 218 may be used to produce and extrude the densesilane-crosslinked polyolefin elastomer while a second reactive singlescrew extruder 218 may be used to produce and extrude the dynamic ormicrodense silane-crosslinked polyolefin elastomer. The complexity andarchitecture of the final static sealing member 12 will determine thenumber and types of reactive single screw extruder 218.

It is understood that the description outlining and teaching the variousstatic sealing members 12 and their respective components/compositionpreviously discussed, which can be used in any combination, appliesequally well to the method 300 for making the static sealing memberusing the two-step Sioplas process as shown.

Referring now to FIGS. 10 and 11, a method 400 for making a static seal,such as static sealing member 12, using the one-step Monosil process isshown. The method 400 may begin with a step 404 that includes extruding(e.g., with a single screw extruder 230) the first polyolefin 170 havinga density less than 0.86 g/cm³, the second polyolefin 174, the silancocktail 178 including the the silane crosslinker (e.g., vinyltrimethoxysilane, VTMO) and grafting initiator (e.g. dicumyl peroxide), and thecondensation catalyst 210 together to form the crosslinkablesilane-grafted polyolefin blend. The first polyolefin 170, secondpolyolefin 174, and silan cocktail 178 may be added to the reactivesingle screw extruder 230 using an addition hopper 186. In some aspects,the silan cocktail 178 may be added to a single screw 234 further downthe extrusion line to help promote better mixing with the first andsecond polyolefin 170, 174 blend. In some aspects, one or more optionaladditives 214 may be added with the first polyolefin 170, secondpolyolefin 174, and silan cocktail 178 to tweak the final materialproperties of the silane-crosslinkable polyolefin blend 212. The singlescrew extruder 182 is considered reactive because the radical initiatorand silane crosslinker of the silan cocktail 178 are reacting with andforming new covalent bonds with both the first and second polyolefinblends 170, 174. In addition, the reactive single screw extruder 230mixes the condensation catalyst 210 in together with the meltedsilane-grafted polyolefin blend. The melted silane-crosslinkablepolyolefin blend 212 can exit the reactive single screw extruder 230using a gear pump (not shown) and/or die that can inject, eject, and/orextrude the molten silane-crosslinkable polyolefin blend into theuncured static sealing element.

During step 404, as the first polyolefin 170, second polyolefin 174,silan cocktail 178, and condensation catalyst 210 are extruded together,a certain amount of crosslinking may occur in the reactive single screwextruder 230 (see FIGS. 10 and 11). In some aspects, thesilane-crosslinkable polyolefin blend 212 may be about 25% cured, about30% cured, about 35% cured, about 40% cured, about 45% cured, about 50%cured, about 55% cured, about 60% cured, bout 65% cured, or about 70% asit leaves the reactive single screw extruder 230. The gel test (ASTMD2765) can be used to determine the amount of crosslinking in the finaldense silane-crosslinked polyolefin elastomer.

The reactive single screw extruder 230 can be configured to have aplurality of different temperature zones (e.g., Z0-Z7 as shown in FIG.11) that extend for various lengths along the extruder. In some aspects,the respective temperature zones may have temperatures ranging fromabout room temperature to about 180° C., from about 120° C. to about170° C., from about 120° C. to about 160° C., from about 120° C. toabout 150° C., from about 120° C. to about 140° C., from about 120° C.to about 130° C., from about 130° C. to about 170° C., from about 130°C. to about 160° C., from about 130° C. to about 150° C., from about130° C. to about 140° C., from about 140° C. to about 170° C., fromabout 140° C. to about 160° C., from about 140° C. to about 150° C.,from about 150° C. to about 170° C., and from about 150° C. to about160° C. In some aspects, ZO may have a temperature from about 60° C. toabout 110° C. or no cooling; Z1 may have a temperature from about 120°C. to about 130° C.; Z2 may have a temperature from about 140° C. toabout 150° C.; Z3 may have a temperature from about 150° C. to about160° C.; Z4 may have a temperature from about 150° C. to about 160° C.;Z5 may have a temperature from about 150° C. to about 160° C.; Z6 mayhave a temperature from about 150° C. to about 160° C.; and Z7 may havea temperature from about 150° C. to about 160° C.

In some aspects, the number average molecular weight of thesilane-grafted polyolefin elastomers may be in the range of from about4,000 g/mol to about 30,000 g/mol, including from about 5,000 g/mol toabout 25,000 g/mol and from about 6,000 g/mol to about 14,000 g/mol. Theweight average molecular weight of the grafted polymers may be fromabout 8,000 g/mol to about 60,000 g/mol, including from about 10,000g/mol to about 30,000 g/mol.

Still referring to FIGS. 10 and 11, the method 400 further includes astep 408 of molding the silane-crosslinkable polyolefin blend into theuncured static sealing element. The reactive single screw extruder 230can melt and extrude the silane-crosslinkable polyolefin through the diethat can extrude the molten silane-crosslinkable polyolefin blend intothe uncured static sealing element to then be cured into the staticsealing member 12 (see FIGS. 1 and 2), for example, the inner beltstatic seal 134, front pillar static seal 138, and rear pillar staticseal 142.

Still referring to FIG. 10, the method 400 can further include a step412 of crosslinking the silane-crosslinkable polyolefin blend 212 of theuncured static sealing element at an ambient temperature and an ambienthumidity to form the element into the static seal, such as staticsealing member 12 having a density from about 0.85 g/cm³ to about 0.89g/cm³. The amount of crosslinked silane groups, and thus the finalpolymer properties, can be regulated by controlling the productionprocess, including the amount of catalyst used.

The step 412 of crosslinking the silane-crosslinkable polyolefin blendmay occur over a time period of from greater than 0 to about 20 hours.In some aspects, curing takes place over a time period of from about 1hour to about 20 hours, 10 hours to about 20 hours, from about 15 hoursto about 20 hours, from about 5 hours to about 15 hours, from about 1hour to about 8 hours, or from about 3 hours to about 6 hours. Thetemperature during the crosslinking and curing may be about roomtemperature, from about 20° C. to about 25° C., from about 20° C. toabout 150° C., from about 25° C. to about 100° C., or from about 20° C.to about 75° C. The humidity during curing may be from about 30% toabout 100%, from about 40% to about 100% , or from about 50% to about100%.

In some aspects, an extruder setting is used that is capable ofextruding thermoplastic, with long L/D, 30 to 1, at an extruder heatsetting close to TPV processing conditions wherein the extrudatecrosslinks at ambient conditions becoming a thermoset in properties. Inother aspects, this process may be accelerated by steam exposure.Immediately after extrusion, the gel content (also called the crosslinkdensity) may be about 60%, but after 96 hrs at ambient conditions, thegel content may reach greater than about 95%.

In some aspects, one or more reactive single screw extruders 230 (seeFIG. 11) may be used to form the uncured sealing element andcorresponding static sealing member that have one or more types ofsilane-crosslinked polyolefin elastomers. For example, in some aspects,one reactive single screw extruder 230 may be used to produce andextrude the dense silane-crosslinked polyolefin elastomer while a secondreactive single screw extruder 230 may be used to produce and extrudethe dynamic or microdense silane-crosslinked polyolefin elastomer. Thecomplexity and architecture of the final static sealing member 12 willdetermine the number and types of reactive single screw extruder 230.

It is understood that the description outlining and teaching the variousstatic sealing members 12 and their respective components/compositionpreviously discussed, which can be used in any combination, appliesequally well to the method 400 for making the static sealing memberusing the one-step Monosil process as shown.

Non-limiting examples of articles that the dense silane-crosslinkedpolyolefin elastomer of the disclosure may be used to manufactureinclude static seals such as weather seals (e.g., glass run channelsincluding molded details/corners), sunroof seals, convertible top seals,mirror seals, body-panel interface seals, stationary window moldings,glass encapsulations, cut-line seals, greenhouse moldings, occupationdetector system sensor switches, rocker seals, outer and inner belts,auxiliary and margin seals, edge protector/gimp seals, and below-beltbrackets and channels; automotive hoses such as coolant hoses, airconditioning hoses, and vacuum hoses; anti-vibration system (AVS)components such as mounts (e.g., engine, body, accessory, component),dampers, bushings, strut mounts, and isolators; coatings such ascoatings for brake lines, fuel lines, transmission oil cooler lines,brackets, cross members, frame components, body panels and components,suspension components, wheels, hubs, springs, and fasteners; airdeflectors, spoilers, fascia, and trim; building, window, and doorseals; boots, bellows, and grommets; gaskets (e.g., pneumatic and/orhydraulic gaskets); wire and cable sheathing; tires; windshield wipersand squeegees; floor mats; pedal covers; automotive belts; conveyorbelts; shoe components; marine bumpers; O-rings; valves and seals; andsprings (e.g., as substitutes for mechanical metal springs).

Dense Silane-Crosslinked Polyolefin Elastomer Physical Properties

A “thermoplastic”, as used herein, is defined to mean a polymer thatsoftens when exposed to heat and returns to its original condition whencooled to room temperature. A “thermoset”, as used herein, is defined tomean a polymer that solidifies and irreversibly “sets” or “crosslinks”when cured. In either of the Monosil or Sioplas processes describedabove, it is important to understand the careful balance ofthermoplastic and thermoset properties of the various differentmaterials used to produce the final thermoset dense silane-crosslinkedpolyolefin elastomer or static sealing member. Each of the intermediatepolymer materials mixed and reacted using a reactive twin screwextruder, a reactive single screw extruder, and/or a reactive singlescrew extruder are thermosets. Accordingly, the silane-graftedpolyolefin blend and the silane-crosslinkable polyolefin blend arethermoplastics and can be softened by heating so the respectivematerials can flow. Once the silane-crosslinkable polyolefin blend isextruded, molded, pressed, and/or shaped into the uncured sealingelement or other respective article, the silane-crosslinkable polyolefinblend can begin to crosslink or cure at an ambient temperature and anambient humidity to form the static sealing member and densesilane-crosslinked polyolefin blend.

The thermoplastic/thermoset behavior of the silane-crosslinkablepolyolefin blend and corresponding dense silane-crosslinked polyolefinblend are important for the various compositions and articles disclosedherein (e.g., static sealing members 12 shown in FIGS. 1 and 2) becauseof the potential energy savings provided using these materials. Forexample, a manufacturer can save considerable amounts of energy by beingable to cure the silane-crosslinkable polyolefin blend at an ambienttemperature and an ambient humidity. This curing process is typicallyperformed in the industry by applying significant amounts of energy toheat or steam treat crosslinkable polyolefins. The ability to cure theinventive silane-crosslinkable polyolefin blend with ambient temperatureand/or ambient humidity are not properties necessarily intrinsic tocrosslinkable polyolefins, but rather is a property dependent on therelatively low density (i.e., as compared to EPDM and/or TPV) of thesilane-crosslinkable polyolefin blend. In some aspects, no additionalcuring overs, heating ovens, steam ovens, or other forms of heatproducing machinery other than what was provided in the extruders areused to form the dense silane-crosslinked polyolefin elastomers.

The specific gravity of the dense silane-crosslinked polyolefinelastomer of the present disclosure may be lower than the specificgravities of existing TPV and EPDM formulations used in the art. Thereduced specific gravity of these materials can lead to lower weightparts, thereby helping automakers meet increasing demands for improvedfuel economy. For example, the specific gravity of the densesilane-crosslinked polyolefin elastomer of the present disclosure may befrom about 0.80 g/cm³to about 0.89 g/cm³, from about 0.85 g/cm³to about0.89 g/cm³, less than 0.90 g/cm³, less than 0.89 g/cm³, less than 0.88g/cm³, less than 0.87 g/cm³, less than 0.86 g/cm³, or less than 0.85g/cm³ as compared to existing TPV materials which may have a specificgravity of from 0.95 to 1.2 g/cm³ and EPDM materials which may have aspecific gravity of from 1.0 to 1.35 g/cm³. The low specific gravity ordensity of the dense silane-crosslinked polyolefin elastomer isattributable to the low crystallinity of the found in Examples 1-7described below. In some aspects, the percent crystallinity of the densesilane-crosslinked polyolefin elastomer is less than 10%, less than 20%,or less than 30%.

Referring now to FIG. 12, the stress/strain behavior of an exemplarysilane-crosslinked polyolefin elastomer of the present disclosure (i.e.,the “Silane-Crosslinked Polyolefin Elastomer” in the legend) relative totwo existing EPDM materials is provided. In particular, FIG. 12 displaysa smaller area between the stress/strain curves for thesilane-crosslinked polyolefin of the disclosure, versus the areasbetween the stress/strain curves for EPDM compound A and EPDM compoundB. This smaller area between the stress/strain curves for thesilane-crosslinked polyolefin elastomer can be desirable for staticseals/weatherstrips used with automotive glass applications. Elastomericmaterials typically have non-linear stress-strain curves with asignificant loss of energy when repeatedly stressed. Thesilane-crosslinked polyolefin elastomers of the present disclosure mayexhibit greater elasticity and less viscoelasticity (e.g., have linearcurves and exhibit very low energy loss). Embodiments of thesilane-crosslinked polyolefin elastomers described herein do not haveany filler or plasticizer incorporated into these materials so theircorresponding stress/strain curves do not have or display any Mullinseffect and/or Payne effect. The lack of Mullins effect for thesesilane-crosslinked polyolefin elastomers is due to the lack of anyconventional reinforcing fillers (e.g., carbon black) or plasticizeradded to the silane-crosslinked polyolefin blend so the stress-straincurve does not depend on the maximum loading previously encounteredwhere there is no instantaneous and irreversible softening. The lack ofPayne effect for these silane-crosslinked polyolefin elastomers is dueto the lack of any filler or plasticizer added to the silane-crosslinkedpolyolefin blend so the stress-strain curve does not depend on the smallstrain amplitudes previously encountered where there is no change in theviscoelastic storage modulus based on the amplitude of the strain.

The silane-crosslinked polyolefin elastomer or static sealing member canexhibit a compression set of from about 5.0% to about 30.0%, from about5.0% to about 25.0%, from about 5.0% to about 20.0%, from about 5.0% toabout 15.0%, from about 5.0% to about 10.0%, from about 10.0% to about25.0%, from about 10.0% to about 20.0%, from about 10.0% to about 15.0%,from about 15.0% to about 30.0%, from about 15.0% to about 25.0%, fromabout 15.0% to about 20.0%, from about 20.0% to about 30.0%, or fromabout 20.0% to about 25.0%, as measured according to ASTM D 395 (22 hrs@ 23° C., 70° C., 80° C,. 90° C., 125° C., and/or 175° C.).

In other implementations, the silane-crosslinked polyolefin elastomer orstatic sealing member can exhibit a compression set of from about 5.0%to about 20.0%, from about 5.0% to about 15.0%, from about 5.0% to about10.0%, from about 7.0% to about 20.0%, from about 7.0% to about 15.0%,from about 7.0% to about 10.0%, from about 9.0% to about 20.0%, fromabout 9.0% to about 15.0%, from about 9.0% to about 10.0%, from about10.0% to about 20.0%, from about 10.0% to about 15.0%, from about 12.0%to about 20.0%, or from about 12.0% to about 15.0%, as measuredaccording to ASTM D 395 (22 hrs @ 23° C., 70° C., 80° C., 90° C., 125°C., and/or 175° C.).

The silane-crosslinked polyolefin elastomers and static sealing membersof the disclosure may exhibit a crystallinity of from about 5% to about40%, from about 5% to about 25%, from about 5% to about 15%, from about10% to about 20%, from about 10% to about 15%, or from about 11% toabout 14% as determined using density measurements, differentialscanning calorimetry (DSC), X-Ray Diffraction, infrared spectroscopy,and/or solid state nuclear magnetic spectroscopy. As disclosed herein,DSC was used to measure the enthalpy of melting in order to calculatethe crystallinity of the respective samples.

The silane-crosslinked polyolefin elastomers and static sealing membersmay exhibit a glass transition temperature of from about −75° C. toabout −25° C., from about −65° C. to about −40° C., from about −60° C.to about −50° C., from about −50° C. to about −25° C., from about −50°C. to about −30° C., or from about −45° C. to about −25° C. as measuredaccording to differential scanning calorimetry (DSC) using a secondheating run at a rate of 5° C/min or 10° C/min.

The silane-crosslinked polyolefin elastomers and static sealing membersmay exhibit a weathering color difference of from about 0.25 ΔE to about2.0 ΔE, from about 0.25 ΔE to about 1.5 ΔE, from about 0.25 ΔE to about1.0 ΔE, or from about 0.25 ΔE to about 0.5 ΔE, as measured according toASTM D2244 after 3000 hrs exposure to exterior weathering conditions.

The silane-crosslinked polyolefin elastomers and static sealing membersmay exhibit exceptional stain resistance properties as compared to EPDMsamples. Ex. 3, as disclosed below, showed no cracking, wrinkling,crazing, iridescence, bloom, milkiness, separation, loss of adhesion, orloss of embossment as measured according to ASTM D1566. In addition, Ex.3 which is representative of all the silane-crosslinked polyolefinelastomers produced, showed no spotting or discoloration in pH 11, pH12.5, and pH 13 NaOH solutions as measured according to SunSimulationand Spotting Test (PR231-2.2.15).

EXAMPLES

The following examples represent certain non-limiting examples of thestatic sealing members, compositions and methods of making them,according to the disclosure.

Materials

All chemicals, precursors and other constituents were obtained fromcommercial suppliers and used as provided without further purification.

Example 1

Example 1 or ED4 was produced by extruding 77.36 wt % ENGAGE 8150 and19.34 wt % VISTAMAX 6102 together with 3.3 wt % SILFIN 13 to form thesilane-grafted polyolefin elastomer. The Example 1 silane-graftedpolyolefin elastomer was then extruded with 3 wt % Ambicat LE4472condensation catalyst to form a silane-crosslinkable polyolefinelastomer, which was then extruded into an uncured static sealingmember. The Example 1 silane-crosslinkable polyolefin elastomer of theuncured static sealing member was cured at ambient temperature andhumidity to form a silane-crosslinked polyolefins elastomer, consistentwith the elastomers of the disclosure. The composition of Example 1 isprovided in Table 1 below.

Example 2

Example 2 or ED76-4A was produced by extruding 82.55 wt % ENGAGE 8842and 14.45 wt % MOSTEN TB 003 together with 3.0 wt % SILAN RHS 14/032 orSILFIN 29 to form the silane-grafted polyolefin elastomer. The Example 2silane-grafted polyolefin elastomer was then extruded with 3 wt %Ambicat LE4472 condensation catalyst to form a silane-crosslinkablepolyolefin elastomer, which was then extruded into an uncured staticsealing member. The Example 2 silane-crosslinkable polyolefin elastomerof the uncured static sealing member was cured at ambient temperatureand humidity to form a silane-crosslinked polyolefins elastomer,consistent with the elastomers of the disclosure. The composition ofExample 2 is provided in Table 1 below and some of its materialproperties are provided in FIGS. 13-18.

Example 3

Example 3 or ED76-4E was produced by extruding 19.00 wt % ENGAGE 8150,58.00 wt % ENGAGE 8842, and 20.00 wt % MOSTEN TB 003 together with 3.0wt % SILAN RHS 14/032 or SILFIN 29 to form the silane-grafted polyolefinelastomer. The Example 3 silane-grafted polyolefin elastomer was thenextruded with 3 wt % Ambicat LE4472 condensation catalyst to form thesilane-crosslinkable polyolefin elastomer, which was then extruded intoan uncured static sealing member. The Example 3 silane-crosslinkablepolyolefin elastomer of the uncured static sealing member was cured atambient temperature and humidity to form a silane-crosslinkedpolyolefins elastomer, consistent with the elastomers of the disclosure.The composition of Example 3 is provided in Table 1 below.

Example 4

Example 4 or ED76-5 was produced by extruding 19.00 wt % ENGAGE 8150,53.00 wt % ENGAGE 8842, and 25.00 wt % MOSTEN TB 003 together with 3.0wt % SILAN RHS 14/032 or SILFIN 29 to form the silane-grafted polyolefinelastomer. The Example 4 silane-grafted polyolefin elastomer was thenextruded with 3 wt % Ambicat LE4472 condensation catalyst to form thesilane-crosslinkable polyolefin elastomer, which was then extruded intoan uncured static sealing member. The Example 4 silane-crosslinkablepolyolefin elastomer of the uncured static sealing member was cured atambient temperature and humidity to form a silane-crosslinkedpolyolefins elastomer, consistent with the elastomers of the disclosure.The composition of Example 4 is provided in Table 1 below.

Example 5

Example 5 or ED76-6 was produced by extruding 16.36 wt % ENGAGE 8150,45.64 wt % ENGAGE 8842, and 35.00 wt % MOSTEN TB 003 together with 3.0wt % SILAN RHS 14/032 or SILFIN 29 to form the silane-grafted polyolefinelastomer. The Example 5 silane-grafted polyolefin elastomer was thenextruded with 3 wt % Ambicat LE4472 condensation catalyst to form thesilane-crosslinkable polyolefin elastomer, which was then extruded intoan uncured static sealing member. The Example 5 silane-crosslinkablepolyolefin elastomer of the uncured static sealing member was cured atambient temperature and humidity to form a silane-crosslinkedpolyolefins elastomer, consistent with the elastomers of the disclosure.The composition of Example 5 is provided in Table 1 below.

Table 1 below sets forth the compositions of the silane-graftedpolyolefin elastomers of Examples 1-5.

TABLE 1 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 ENGAGE 8150 77.36 — 19.00 19.0016.36 ENGAGE 8842 — 82.55 58.00 53.00 45.64 MOSTEN TB 003 — 14.45 20.0025.00 35.00 VISTAMAXX 6102 19.34 — — — — SILAN RHS 14/032 or — 3.00 3.003.00 3.00 SILFIN 29 SILFIN 13 3.30 — — — — TOTAL 100 100 100 100 100

Example 6

Example 6 or ED108-2A was produced by extruding 48.7 wt % ENGAGE XLT8677or XUS 38677.15 and 48.7 wt % ENGAGE 8842 together with 2.6 wt % SILANRHS 14/032 or SILFIN 29 to form the silane-grafted polyolefin elastomer.The Example 6 silane-grafted polyolefin elastomer was then extruded withabout 360 ppm dioctyltin dilaurate (DOTL) condensation catalyst to forma silane-crosslinkable polyolefin elastomer as an uncured static sealingmember. The Example 6 silane-crosslinkable polyolefin elastomer of theuncured static sealing member was cured at ambient temperature andhumidity to form a silane-crosslinked polyolefins elastomer, consistentwith the elastomers of the disclosure. The composition of Example 6 isprovided in Table 2 below and some of its material properties areprovided in FIGS. 13-18.

Example 7

Example 7 or ED92 was produced by extruding 41.4 wt % ENGAGE XLT8677 orXUS 38677.15 and 41.4 wt % ENGAGE 8842, and 14.4 wt % MOSTEN TB 003together with 2.8 wt % SILAN RHS 14/032 or SILFIN 29 to form thesilane-grafted polyolefin elastomer. The Example 7 silane-graftedpolyolefin elastomer was then extruded with about 360 ppm dioctyltindilaurate (DOTL) condensation catalyst to form a silane-crosslinkablepolyolefin elastomer as an uncured static sealing member. The Example 7silane-crosslinkable polyolefin elastomer of the uncured static sealingmember was cured at ambient temperature and humidity to form asilane-crosslinked polyolefins elastomer, consistent with the elastomersof the disclosure. The composition of Example 7 is provided in Table 2below and some of its material properties are provided in FIGS. 13-18.

Table 2 below sets forth the compositions of the silane-graftedpolyolefin elastomers of Examples 6-7.

TABLE 2 Ingredients Ex. 6 Ex. 7 ENGAGE XLT8677/XUS 38677.15 48.7 41.4ENGAGE 8842 48.7 41.4 SILAN RHS 14/032 or SILFIN 29 2.6 2.8 MOSTEN TB003 — 14.4 TOTAL 100 100

Table 3 below sets forth several of the material properties ofExample 1. In particular, plied compression set percentages are providedusing ASTM D 395, method B for 22 hrs at 23 ° C., 70° C., 80° C., 90°C., 125° C., and 175° C. Example 1 is representative the densesilane-crosslinked polyolefin elastomers disclosed herein in that thecompression set percentage does not vary as much as standard EPDM or TPVmaterials do across a range of different temperatures. In some aspects,the percent difference in plied compression set percentage values forthe dense silane-crosslinked polyolefin elastomer is less than 400%,less than 300%, less than 275%, less than 250%, less than 225%, or lessthan 210%.

TABLE 3 Test Ex. 1 Durometer (Type A per ASTM D 2240) 75 Tensile MPa(ASTM D 412, die C) 9.8 Elongation % (ASTM D 412, die C) 291 TearResistance (ASTM D624, die C) 19 22 hrs/23° C. Plied Compression Set %20.0 22 hrs/70° C. Plied Compression Set % 12.6 22 hrs/80° C. PliedCompression Set 16.5 22 hrs/90° C. Plied Compression Set % 10.9 22hrs/125° C. Plied Compression Set % 7.6 22 hrs/175° C. Plied CompressionSet % 9.6 Gel % 90

Table 4 below sets forth density, hardness, low and high temperatureperformance, compression set, and weathering material properties forExamples 2-4.

TABLE 4 Property Test Method Units/Output Ex. 2 Ex. 3 Ex. 4 OriginalsDensity ASTM D297 g/cc 0.88 0.89 0.89 Hardness ASTM D412 Shore A 76 8488 Die C Tensile ASTM D412 MPa 10.4 13.2 14.5 Die C Elongation ASTM D412% 300 306 314 Die C Tear C ASTM D624 N/mm 24 37 48 Die C Hardness JIS K6253 IRHD 72 82 87 Tensile JIS K 6251 MPa 8.3 13.3 16.1 Elongation JIS K6251 % 260 255 334 Tear C JIS K 6252 N/cm 249 401 564 Low & HighHardness Heat Age (70 h/100° C.) ASTM D573 Change −2 −2 1 Temperature(Shore A) Performance Tensile Heat Age (70 h/100° C.) ASTM D573 % Change−3.1 −6 9.1 Elongation Heat Age (70 h/100° C.) ASTM D573 % Change −10.4−8.7 −2.6 Hardness Heat Age (168 h/100° C.) JIS K 6251/7 Change 0 2 −5(IRHD) Tensile Heat Age (168 h/100° C.) JIS K 6251/7 % Change 0 −15.1−9.9 Elongation Heat Age (168 h/100° C.) JIS K 6251/7 % Change −18 −22.7−21 Tear Heat Age (168 h/100° C.) JIS K 6251/7 % Change −11.2 −8.7 −10Tensile Heat Age (1000 h/125° C.) ASTM D573 Change −2 −1 0 (Shore A)Elongation Heat Age ASTM D573 % Change −4.4 18.7 1.4 (1000 h/125° C.)Tear Heat Age (1000 h/125° C.) ASTM D573 % Change −6.1 −11 −8.8 −40° C.Tensile ASTM D412 % Change 38.5 — — Die C −40° C. Elongation ASTM D412 %Change 17.6 — — Die C Low Temperature (−40° C.) ASTM D2137 — NonbrittleNonbrittle Nonbrittle Method A 80° C. Tensile ASTM D412 % Change −10.8 —— Die C 80° C. Elongation ASTM D412 % Change −1.5 — — Die C CompressionPlied C/S (22 h/70° C.) ASTM D395 % 20.7 25 30 Set Method B Plied C/S(22 h/80° C.) ASTM D395 % 20.2 30.5 — Method B Plied C/S (72 h/80° C.)ASTM D395 % 22.5 32.6 — Method B Plied C/S (100 h/80° C.) ASTM D395 %39.2 44.3 54.7 Method B Plied C/S (168 h/80° C.) ASTM D395 % 29 39 —Method B Plied C/S (500 h/80° C.) ASTM D395 % 41.2 53.8 — Method B PliedC/S (1000 h/80° C.) ASTM D395 % 43.8 55.4 — Method B Plied C/S (22 h/90°C.) ASTM D395 % 22.5 32.8 — Method B Plied C/S (22 h/100° C.) ASTM D395% 25.4 35 42.5 Method B Plied C/S (70 h/125° C.) ASTM D395 % 29 37.946.6 Method B Plied C/S (22 h/135° C.) ASTM D395 % 38.5 46.6 — Method BPlied C/S (22 h/150° C.) ASTM D395 % 44.3 61 — Method B Plied C/S (22h/175° C.) ASTM D395 % 23.3 38.1 — Method B Permanent CompressiveDistortion JIS K 6257 % 30 41 43 (22 h/100° C.) Miscellaneous VolumeResistivity IEC 60093 Ω cm 2.1 × 10¹⁶ 2.2 × 10¹⁶ 2.2 × 10¹⁶ Weathering(3000 hrs.) SAE J2527 AATCC 4-5 4-5 4-5 Arizona Natural Weathering (2yrs.) SAE J1976, ΔE 1.6 1.2 1.7 Procedure A Florida Natural Weathering(2 yrs.) SAE J1976, ΔE 1.6 1.0 1.2 Procedure A Fogging SAE J1756 % 97 9697 Ozone Resistance ASTM D1171 Retention 100 100 100 Method B Rating (%)Flammability ISO 3795 Burn Rate 19 22 17 (mm/min) Odor SAE J1351 No PassPass Pass Disagreeable Odor Wet or Dry Paint Staining (24 h/70° C.) ASTMD925 — No No No Method A Staining Staining Staining

Table 5 below sets forth the chemical resistance material properties forExample 2, which is representative of all of the disclosed densesilane-crosslinked polyolefin elastomers. Method B includes reportingany evidence of softening, staining, blistering, flaking, chipping,checking, chalking, cracks, spills, sinks, bulges, tackiness, peeling,or delamination. The fairness grade is 5 for a CELAB difference of 0 anda Tolerance of 0.2 and the fairness grade is 4 for a CELAB difference of1.7 and a Tolerance of ±.3.

TABLE 5 Test Chemical Method Units/Output Ex. 2 Solvent Resistance 7:3(Kerosene:Mineral Spirits) TSM1720G % Change in 170 (72 h/RT) VolumeFluid Resistance Gasoline 87 Octane, Lead Free, 20% FLTM BI 168-01,Rating (see Pass, 4 Ethanol Method B above) Diesel, Grade 2, 20%Biodiesel FLTM BI 168-01, Rating (see Pass, 4 Method B above) Coolant,Ethylene glycol/Water 50/50 FLTM BI 168-01, Rating (see Pass, 5 Method Babove) Engine Oil, Meets API-ILSAC Requirements FLTM BI 168-01, Rating(see Pass, 5 Method B above) Deionized Water FLTM BI 168-01, Rating (seePass, 5 Method B above) Multipurpose Cleaner (Formula 409, FLTM BI168-01, Rating (see Pass, 5 Fantastic, or Armor All) Method B above)Windshield Wash Fluid, Methanol Based, 1 FLTM BI 168-01, Rating (seePass, 5 Part Motorcraft Fluid to 1.5 Parts Water Method B above)Motorcraft Bug and Tar Remover FLTM BI 168-01, Rating (see Pass, 5Method B above) Glass Cleaner FLTM BI 168-01, Rating (see Pass, 5 MethodB above) Isopropyl Alcohol 1:1 with Water FLTM BI 168-01, Rating (seePass, 5 Method B above)

Referring now to FIG. 13, the compression set percentage is given byC_(B)=[(H₀-H₀′)/(H₀-H_(comp)×)100% where H₀ is the original specimenthickness before compression, H₀′ is the specimen thickness aftertesting, and H_(comp) is the specimen thickness during the test. Asprovided in FIG. 13, each of Examples 2, 6, and 7 (“Exs. 2, 6 and 7” inFIG. 13) made from the dense silane-crosslinked polyolefin elastomersexhibited a lower compression set after one hour and a higher speed ofset recovery as compared to TOSE 539 70 (“TPS” in FIG. 13), a styrenicTPV or TPS, and SANTOPRENE 12167W175 (“EPDM/PP” in FIG. 13), a EPDM/PPcopolymer. The compression set percentages provided by each of the densesilane-crosslinked polyolefin elastomers (Exs. 2, 6 and 7) relative tothe comparative TPV and EPDM materials demonstrate the improved highelastic properties exhibited by these materials.

Referring now to FIG. 14, the lip set recovery percentage is given byLSR=[(L₀′)/(L₀)×100% where L₀is the original lip thickness beforecompression and L₀′ is the lip thickness after testing. As provided inFIG. 14, each of Examples 2, 6, and 7 made from the densesilane-crosslinked polyolefin elastomers exhibited a higher lip setrecovery after one hour (97%, 97.5%, and 99.2%, respectively) and ahigher speed of lip set recovery as compared to TPS (93%) or EPDM/PPcopolymer (94%). Again, the lip set recovery percentages provided byeach of the dense silane-crosslinked polyolefin elastomers relative toTPV and EPDM materials demonstrate the improved elastic propertiesexhibited by these materials.

Referring now to FIG. 15, the lip relaxation rate percentage for 1 hr at23° C. is given by R(%)=(F₀-F_(t))/(F₀) where Fo is the initial forcerequired for the first compression and F_(t) is the final force requiredfor compression for the testing period. As provided in FIG. 15, each ofExamples 2, 6, and 7 made from the dense silane-crosslinked polyolefinelastomers exhibited an improved relaxation rate as compared to TPS orEPDM/PP copolymer.

Referring now to FIG. 16, the stress/strain behavior of an exemplarydense silane-crosslinked polyolefin elastomer of the present disclosureis provided. The traces in FIG. 16 demonstrate the particularly smallareas that can be achieved between the stress/strain curves for thesilane-crosslinked polyolefin of the disclosure. Elastomeric materialstypically have non-linear stress-strain curves with a significant lossof energy when repeatedly stressed. The silane-crosslinked polyolefinelastomers of the present disclosure exhibit greater elasticity and lessviscoelasticity (e.g., have linear curves and exhibit very low energyloss). The lack of any filler or plasticizer in these materials lead tono demonstration of any Mullins and/or Payne effect.

Referring now to FIG. 18, compression set performance is provided acrossa range of elevated temperatures and increasing periods of time forExample 1, a comparative TPV, and a comparative EPDM. As shown in thegraph, the compression set % of the dense silane-crosslinked polyolefinelastomer (Ex. 1) increases slightly over the provided increasingtemperatures (23° C.-175° C.) for a test time of 22 h relative to thecomparative TPV and EPDM materials. The compression set % of the Ex. 1dense silane-crosslinked polyolefin elastomer stays surprisingly evenacross the provided temperature range as compared to the dramaticincrease in compression set % demonstrated for the TPV and EPDMmaterials.

Referring now to FIG. 17, compression set performance is provided acrossa range of elevated temperatures and increasing periods of time forExample 1, a comparative TPV, and acomparative EPDM. As shown in thegraph, the compression set % of the dense silane-crosslinked polyolefinelastomer (Ex. 1) increases slightly over the provided increasingtemperatures (70° C.-175° C.) and test times (22 h-1000 h) relative tothe comparative TPV and EPDM materials.

FIG. 19 and Table 6 below provide additional data regarding thecompression set performance of Examples 2-4 relative to EPDM 9724 andTPV 121-67. Table 6 provides compression set data performed intriplicate for Examples 2-4 relative to EPDM 9724 (“EPDM”) and TPV121-67 (“TPV”). FIG. 19 plots the average compression set values forthese samples performed at 72 hrs at 23° C. and 70 hrs at 125° C.

TABLE 6 Compound 72 h/23° C. 70 h/125° C. Ex. 2 13.8 22.1 Ex. 2 15.722.3 Ex. 2 20.4 22.9 Avg. 16.6 22.4 Ex. 3 19.9 31.0 Ex. 3 21.4 33.6 Ex.3 23.6 33.6 Avg. 21.6 32.7 Ex. 4 24.8 41.9 Ex. 4 24.6 40.2 Ex. 4 28.440.0 Avg. 25.9 40.7 EPDM 5.6 75.4 EPDM 8.3 76.3 EPDM 11.5 82.3 Avg. 8.578.0 TPV 21.2 51.2 TPV 21.4 52.4 TPV 21.5 47.8 Avg. 21.4 50.5

For purposes of this disclosure, the term “coupled” (in all of itsforms, couple, coupling, coupled, etc.) generally means the joining oftwo components directly or indirectly to one another. Such joining maybe stationary in nature or movable in nature. Such joining may beachieved with the two components and any additional intermediate membersbeing integrally formed as a single unitary body with one another orwith the two components. Such joining may be permanent in nature or maybe removable or releasable in nature unless otherwise stated.

It is also important to note that the construction and arrangement ofthe elements of the device as shown in the exemplary embodiments isillustrative only. Although only a few embodiments of the presentinnovations have been described in detail in this disclosure, thoseskilled in the art who review this disclosure will readily appreciatethat many modifications are possible (e.g., variations in sizes,dimensions, structures, shapes and proportions of the various elements,values of parameters, mounting arrangements, use of materials, colors,orientations, etc.) without materially departing from the novelteachings and advantages of the subject matter recited. For example,elements shown as integrally formed may be constructed of multiple partsor elements shown as multiple parts may be integrally formed, theoperation of the interfaces may be reversed or otherwise varied, thelength or width of the structures and/or members or connector or otherelements of the system may be varied, the nature or number of adjustmentpositions provided between the elements may be varied. It should benoted that the elements and/or assemblies of the system may beconstructed from any of a wide variety of materials that providesufficient strength or durability, in any of a wide variety of colors,textures, and combinations. Accordingly, all such modifications areintended to be included within the scope of the present innovations.Other substitutions, modifications, changes, and omissions may be madein the design, operating conditions, and arrangement of the desired andother exemplary embodiments without departing from the spirit of thepresent innovations.

It will be understood that any described processes or steps withindescribed processes may be combined with other disclosed processes orsteps to form structures within the scope of the present device. Theexemplary structures and processes disclosed herein are for illustrativepurposes and are not to be construed as limiting.

The above description is considered that of the illustrated embodimentsonly.

Modifications of the device will occur to those skilled in the art andto those who make or use the device. Therefore, it is understood thatthe embodiments shown in the drawings and described above is merely forillustrative purposes and not intended to limit the scope of thearticles, processes and compositions, which are defined by the followingclaims as interpreted according to the principles of patent law,including the Doctrine of Equivalents.

LISTING OF NON-LIMITING EMBODIMENTS

Embodiment A is a static sealing member comprising: a compositioncomprising a silane-crosslinked polyolefin elastomer having a densityless than 0.90 g/cm³, wherein the static sealing member exhibits acompression set of from about 5.0% to about 35.0%, as measured accordingto ASTM D 395 (22 hrs @ 70° C.).

The sealing member of Embodiment A wherein the silane-crosslinkedpolyolefin elastomer comprises a first polyolefin having a density lessthan 0.86 g/cm³, a second polyolefin having a percent crystallinity lessthan 40%, a silane crosslinker, a grafting initiator, and a non-metalcondensation catalyst.

The sealing member of Embodiment A or Embodiment A with any of theintervening features wherein the compression set is from about 15.0% toabout 35.0%, as measured according to ASTM D 395 (22 hrs @ 70° C.).

The sealing member of Embodiment A or Embodiment A with any of theintervening features wherein the density is from about 0.85 g/cm³ toabout 0.89 g/cm³.

The sealing member of Embodiment A or Embodiment A with any of theintervening features wherein the silane-crosslinked polyolefin elastomerexhibits a crystallinity of from about 5% to about 25%.

The sealing member of Embodiment A or Embodiment A with any of theintervening features wherein the silane-crosslinked polyolefin elastomerexhibits a glass transition temperature of from about −75° C. to about−25° C.

The sealing member of Embodiment A or Embodiment A with any of theintervening features wherein the composition is a thermoset, butexhibits thermoplastic properties during processing.

The sealing member of Embodiment A or Embodiment A with any of theintervening features wherein the static sealing member exhibits aweathering color difference of from about 0.25 ΔE to about 2.0 ΔE, asmeasured according to ASTM D2244.

The sealing member of Embodiment A or Embodiment A with any of theintervening features further comprising: a coloring agent.

Embodiment B is a silane-crosslinked polyolefin blend comprising: afirst polyolefin having a density less than 0.86 g/cm³; a secondpolyolefin having a percent crystallinity less than 40%; and a silanecrosslinker, wherein the silane-crosslinked polyolefin blend exhibits acompression set of from about 5.0% to about 35.0%, as measured accordingto ASTM D 395 (22 hrs @ 70° C.).

The silane-crosslinked polyolefin blend of Embodiment B wherein thefirst polyolefin comprises an ethylene octene copolymer from about 60 wt% to about 97 wt %.

The silane-crosslinked polyolefin blend of Embodiment B or Embodiment Bwith any of the intervening features wherein the second polyolefincomprises a polypropylene homopolymer from about 10 wt % to about 35 wt% and/or a poly(ethylene-co-propylene).

The silane-crosslinked polyolefin blend of Embodiment B or Embodiment Bwith any of the intervening features wherein the silane crosslinkercomprises a vinyltrimethoxy silane from about 1 wt % to about 4 wt %.

The silane-crosslinked polyolefin blend of Embodiment B or Embodiment Bwith any of the intervening features further comprising a non-metalcondensation catalyst that comprises a sulfonic ester from about 1 wt %to about 4 wt %.

The silane-crosslinked polyolefin blend of Embodiment B or Embodiment Bwith any of the intervening features wherein the blend has a densityfrom about 0.85 g/cm³ to about 0.89 g/cm³.

The silane-crosslinked polyolefin blend of Embodiment B or Embodiment Bwith any of the intervening features wherein the blend exhibits acrystallinity of from about 5% to about 25%.

The silane-crosslinked polyolefin blend of Embodiment B or Embodiment Bwith any of the intervening features wherein the blend exhibits a glasstransition temperature of from about −75° C. to about −25° C.

Embodiment C is a method for making a static sealing member, the methodcomprising:

extruding a first polyolefin having a density less than 0.86 g/cm³, asecond polyolefin having a crystallinity less than 40%, a silanecrosslinker and a grafting initiator together to form a silane-graftedpolyolefin blend; extruding the silane-grafted polyolefin blend and acondensation catalyst together to form a silane-crosslinkable polyolefinblend; molding the silane-crosslinkable polyolefin blend into an uncuredstatic sealing element; and crosslinking the crosslinkable-polyolefinblend of the uncured static sealing element at an ambient temperatureand an ambient humidity to form the element into a static sealing memberhaving a density from about 0.85 g/cm³ to about 0.89 g/cm³, wherein thestatic sealing member exhibits a compression set of from about 5.0% toabout 35.0%, as measured according to ASTM D 395 (22 hrs @ 70° C.).

The method of Embodiment C wherein the silane-grafted polyolefin blendand the crosslinkable-polyolefin blend are thermoplastics and thecrosslinked polyolefin blend is a thermoset.

The method of Embodiment C or Embodiment C with any of the interveningfeatures wherein the first polyolefin is an ethylene/α-olefin copolymerand the second polyolefin is a polypropylene homopolymer and/or apoly(ethylene-co-propylene).

What is claimed is:
 1. A static sealing member comprising: a compositioncomprising a silane-crosslinked polyolefin elastomer having a densityless than 0.90 g/cm³, wherein the static sealing member exhibits acompression set of from about 5.0% to about 35.0%, as measured accordingto ASTM D 395 (22 hrs @ 70° C.).
 2. The static sealing member of claim1, wherein the silane-crosslinked polyolefin elastomer comprises a firstpolyolefin having a density less than 0.86 g/cm³, a second polyolefinhaving a percent crystallinity less than 40%, a silane crosslinker, agrafting initiator, and a non-metal condensation catalyst.
 3. The staticsealing member of claim 1, wherein the compression set is from about15.0% to about 35.0%, as measured according to ASTM D 395 (22 hrs @ 70°C.).
 4. The static sealing member of claim 1, wherein the density isfrom about 0.85 g/cm³ to about 0.89 g/cm³.
 5. The static sealing memberof claim 1, wherein the silane-crosslinked polyolefin elastomer exhibitsa crystallinity of from about 5% to about 25%.
 6. The static sealingmember of claim 1, wherein the silane-crosslinked polyolefin elastomerexhibits a glass transition temperature of from about −75° C. to about−25° C.
 7. The static sealing member of claim 1, wherein the compositionis a thermoset, but exhibits thermoplastic properties during processing.8. The static sealing member of claim 1, wherein the static sealingmember exhibits a weathering color difference of from about 0.25 AE toabout 2.0 AE, as measured according to ASTM D2244.
 9. The static sealingmember of claim 1, further comprising: a coloring agent.
 10. Asilane-crosslinked polyolefin blend comprising: a first polyolefinhaving a density less than 0.86 g/cm³; a second polyolefin having apercent crystallinity less than 40%; and a silane crosslinker, whereinthe silane-crosslinked polyolefin blend exhibits a compression set offrom about 5.0% to about 35.0%, as measured according to ASTM D 395 (22hrs @ 70° C.).
 11. The silane-crosslinked polyolefin blend of claim 10,wherein the first polyolefin comprises an ethylene octene copolymer fromabout 60 wt % to about 97 wt %.
 12. The silane-crosslinked polyolefinblend of claim 10, wherein the second polyolefin comprises apolypropylene homopolymer from about 10 wt % to about 35 wt % and/or apoly(ethylene-co-propylene).
 13. The silane-crosslinked polyolefin blendof claim 10, wherein the silane crosslinker comprises a vinyltrimethoxysilane from about 1 wt % to about 4 wt %.
 14. The silane-crosslinkedpolyolefin blend of claim 10, further comprising a non-metalcondensation catalyst that comprises a sulfonic ester from about 1 wt %to about 4 wt %.
 15. The silane-crosslinked polyolefin blend of claim10, wherein the blend has a density from about 0.85 g/cm³ to about 0.89g/cm³.
 16. The silane-crosslinked polyolefin blend of claim 10, whereinthe blend exhibits a crystallinity of from about 5% to about 25%. 17.The silane-crosslinked polyolefin blend of claim 10, wherein the blendexhibits a glass transition temperature of from about -75° C. to about-25° C.
 18. A method for making a static sealing member, the methodcomprising: extruding a first polyolefin having a density less than 0.86g/cm³, a second polyolefin having a crystallinity less than 40%, asilane crosslinker and a grafting initiator together to form asilane-grafted polyolefin blend; extruding the silane-grafted polyolefinblend and a condensation catalyst together to form asilane-crosslinkable polyolefin blend; molding the silane-crosslinkablepolyolefin blend into an uncured static sealing element; andcrosslinking the crosslinkable-polyolefin blend of the uncured staticsealing element at an ambient temperature and an ambient humidity toform the element into a static sealing member having a density fromabout 0.85 g/cm³ to about 0.89 g/cm³, wherein the static sealing memberexhibits a compression set of from about 5.0% to about 35.0%, asmeasured according to ASTM D 395 (22 hrs @ 70° C.).
 19. The method ofclaim 18, wherein the silane-grafted polyolefin blend and thecrosslinkable-polyolefin blend are thermoplastics and the crosslinkedpolyolefin blend is a thermoset.
 20. The method of claim 18, wherein thefirst polyolefin is an ethylene/α-olefin copolymer and the secondpolyolefin is a polypropylene homopolymer and/or apoly(ethylene-co-propylene).